@string{brics =	"{BRICS}"}
@string{daimi =	"Department of Computer Science, University of Aarhus"}
@string{iesd  =	"Department of Computer Science, Institute
of Electronic Systems, Aalborg University"}
@string{rs    =	"Research Series"}
@string{ns    =	"Notes Series"}
@string{ls    =	"Lecture Series"}
@string{ds    =	"Dissertation Series"}

TechReport{BRICS-RS-05-,
author =	 "",
title =	 "",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-",
OPTkey =	 "",
OPTmonth =	 "",
OPTnote =	 "~pp",
OPTabstract =	 "",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-38,
author =	 "Biernacka, Ma{\l}gorzata and Danvy, Olivier",
title =	 "A Syntactic Correspondence between Context-Sensitive
Calculi and Abstract Machines",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-38",
OPTkey =	 "",
month =	 dec,
note =	 "iii+39~pp. Revised version of BRICS RS-05-22",
abstract =	 "We present a systematic construction of
environment-based abstract machines from
context-sensitive calculi of explicit substitutions,
and we illustrate it with ten calculi and machines
for applicative order with an abort operation,
normal order with generalized reduction and call/cc,
the lambda-mu-calculus, delimited continuations,
stack inspection, proper tail-recursion, and lazy
evaluation. Most of the machines already exist but
have been obtained independently and are only
indirectly related to the corresponding calculi. All
of the calculi are new and they make it possible to
directly reason about the execution of the
corresponding machines.\bibpar In connection with
the functional correspondence between evaluation
functions and abstract machines initiated by
Reynolds, the present syntactic correspondence makes
it possible to construct reduction-free
normalization functions out of reduction-based ones,
which was an open problem in the area of
normalization by evaluation.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-37,
author =	 "Brodal, Gerth St{\o}lting and Kaligosi, Kanela and
Katriel, Irit and Kutz, Martin",
title =	 "Faster Algorithms for Computing Longest Common
Increasing Subsequences",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-37",
OPTkey =	 "",
month =	 dec,
note =	 "16~pp",
abstract =	 "We present algorithms for finding a longest common
increasing subsequence of two or more input
sequences. For two sequences of lengths $m$ and $n$,
where $m\ge n$, we present an algorithm with an
output-dependent expected running time of
$O((m+n\ell) \log\log \sigma + \mathit{Sort})$ and
$O(m)$ space, where $\ell$ is the length of a LCIS,
$\sigma$ is the size of the alphabet, and
$\mathit{Sort}$ is the time to sort each input
sequence.\bibpar For $k\ge 3$ length-$n$ sequences
we present an algorithm running time
$O(\min\{kr^2,r\log^{k-1}r\}+\mathit{Sort})$, which
improves the previous best bound by more than a
factor $k$ for many inputs. In both cases, our
algorithms are conceptually quite simple but rely on
existing sophisticated data structures.\bibpar
Finally, we introduce the problem of longest common
weakly-increasing (or non-decreasing) subsequences
(LCWIS), for which we present an $O(m+n\log n)$ time
algorithm for the 3-letter alphabet case. For the
extensively studied Longest Common Subsequence
problem, comparable speedups have not been achieved
for small alphabets.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-36,
author =	 "Biernacki, Dariusz and Danvy, Olivier and Shan,
Chung-chieh",
title =	 "On the Static and Dynamic Extents of Delimited
Continuations",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-36",
OPTkey =	 "",
month =	 dec,
note =	 "ii+33~pp. To appear in the journal {\em Science of
Computer Programming}. Supersedes BRICS RS-05-13",
keywords =	 "Delimited continuations, direct style,
continuation-passing style (CPS), CPS
transformation, defunctionalization, control
operators, shift and reset, control and prompt",
abstract =	 "We show that breadth-first traversal exploits the
difference between the static delimited-control
operator shift (alias S) and the dynamic
delimited-control operator control (alias F). For
the last 15 years, this difference has been
repeatedly mentioned in the literature but it has
only been illustrated with one-line toy
vacuum.\bibpar We also point out where static
delimited continuations naturally give rise to the
notion of control stack whereas dynamic delimited
continuations can be made to account for a notion of
control queue.'",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-35,
author =	 "St{\o}vring, Kristian",
title =	 "Extending the Extensional Lambda Calculus with
Surjective Pairing is Conservative",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-35",
OPTkey =	 "",
month =	 nov,
note =	 "19~pp.",
abstract =	 "We answer Klop and de Vrijer's question whether
adding surjective-pairing axioms to the extensional
lambda calculus yields a conservative extension. The
answer is positive. As a byproduct we obtain the
first syntactic'' proof that the extensional
lambda calculus with surjective pairing is
consistent",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-34,
author =	 "Rohde, Henning Korsholm",
title =	 "Formal Aspects of Polyvariant Specialization",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-34",
OPTkey =	 "",
month =	 nov,
note =	 "27~pp",
abstract =	 "We present the first formal correctness proof of an
offline polyvariant specialization algorithm for
first-order recursive equations. As a corollary, we
show that the specialization algorithm generates a
program implementing the search phase of the
Knuth-Morris- Pratt algorithm from an inefficient
but binding-time-improved string matcher",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-33,
author =	 "Aceto, Luca and Fokkink, Willem Jan and
Ing{\'o}lfsd{\'o}ttir, Anna and Nain, Sumit",
title =	 "Bisimilarity is not Finitely Based over {BPA} with
Interrupt",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-33",
OPTkey =	 "",
month =	 oct,
note =	 "33~pp. This paper supersedes BRICS Report
RS-04-24. An extended abstract of this paper
appeared in \emph{Algebra and Coalgebra in Computer
Science, 1st Conference, CALCO 2005}, Swansea,
Wales, 3--6 September 2005, Lecture Notes in
Computer Science 3629, pp.~54--68, Springer-Verlag,
2005",
abstract =	 "This paper shows that bisimulation equivalence does
not afford a finite equational axiomatization over
the language obtained by enriching Bergstra and
Klop's Basic Process Algebra with the interrupt
operator. Moreover, it is shown that the collection
of closed equations over this language is also not
finitely based. In sharp contrast to these results,
the collection of closed equations over the language
BPA enriched with the disrupt operator is proven to
be finitely based",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-32,
author =	 "M{\o}ller, Anders and Olesen, Mads {\O}sterby and
Schwartzbach, Michael I.",
title =	 "Static Validation of {XSL} Transformations",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-32",
OPTkey =	 "",
month =	 oct,
note =	 "50~pp",
abstract =	 "XSL Transformations (XSLT) is a programming
language for defining transformations between XML
languages. The structure of these languages is
formally described by schemas, for example using
DTD, which allows individual documents to be
validated. However, existing XSLT tools offer no
static guarantees that, under the assumption that
the input is valid relative to the input schema, the
output of the transformation is valid relative to
the output schema.\bibpar We present a validation
technique for XSLT based on the summary graph
formalism introduced in the static analysis of JWIG
Web services. Being able to provide static
guarantees, we can detect a large class of errors in
an XSLT stylesheet at the time it is written instead
of later when it has been deployed, and thereby
provide benefits similar to those of static type
checkers for modern programming languages.\bibpar
Our analysis takes a pragmatic approach that focuses
its precision on the essential language features but
still handles the entire XSLT 1.0 language. We
evaluate the analysis precision on a range of real
stylesheets and demonstrate how it may be useful in
practice",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-31,
author =	 "Kirkegaard, Christian and M{\o}ller, Anders",
title =	 "Type Checking with XML Schema in \textsc{Xact}",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-31",
OPTkey =	 "",
month =	 sep,
note =	 "20~pp",
abstract =	 "We show how to extend the program analysis technique
used in the \textsc{Xact} system to support XML
Schema as type formalism. Moreover, we introduce
optional type annotations to improve modularity of
the type checking. The resulting system supports a
flexible style of programming XML transformations
and provides static guarantees of validity of the
generated XML data.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-30,
author =	 "Krukow, Karl",
title =	 "An Operational Semantics for Trust Policies",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-30",
OPTkey =	 "",
month =	 sep,
note =	 "38~pp",
abstract =	 "In the trust-structure model of trust management,
principals specify their trusting relationships with
other principals in terms of trust policies. In
their paper on trust structures, Carbone et
al. present a language for trust policies, and
provide a suitable denotational semantics. The
semantics ensures that for any collection of trust
policies, there is always a unique global
trust-state, compatible with all the policies,
specifying everyone's degree of trust in everyone
else. However, as the authors themselves point out,
the language lacks an operational model: the global
trust-state is a well-defined mathematical object,
but it is not clear how principals can actually
compute it. This becomes even more apparent when one
considers the intended application environment: vast
numbers of autonomous principals, distributed and
possibly mobile. We provide a compositional
operational semantics for a language of trust
policies. The operational semantics is given in
terms of a composition of I/O automata. We prove
that this semantics is faithful to its corresponding
denotational semantics, in the sense that any run of
the I/O automaton converges to'' the denotational
semantics of the policies. Furthermore, as I/O
automata are a natural model of asynchronous
distributed computation, the semantics leads to an
algorithm for distributedly computing the
trust-state, which is suitable in the application
environment",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-29,
author =	 "Danvy, Olivier and Rohde, Henning Korsholm",
title =	 "On Obtaining the {B}oyer-{M}oore String-Matching
Algorithm by Partial Evaluation",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-29",
OPTkey =	 "",
month =	 sep,
note =	 "ii+9~pp. To appear in {\em Information Processing
Letters}. This version supersedes BRICS RS-05-14",
abstract =	 "We present the first derivation of the search phase
of the Boyer-Moore string-matching algorithm by
partial evaluation of an inefficient string
matcher. The derivation hinges on identifying the
binding-time improvement, bounded static
variation. An inefficient string matcher
incorporating this binding-time improvement
specializes into the search phase of the Horspool
algorithm, which is a simplified variant of the
Boyer-Moore algorithm. Combining the
with our previous results yields a new
binding-time-improved string matcher that
specializes into the search phase of the Boyer-Moore
algorithm",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-28,
author =	 "Srba, Ji{\v{r}}{\'\i}",
title =	 "On Counting the Number of Consistent Genotype
Assignments for Pedigrees",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-28",
OPTkey =	 "",
month =	 sep,
note =	 "15~pp. To appear in FSTTCS~'05",
abstract =	 "Consistency checking of genotype information in
pedigrees plays an important role in genetic
analysis and for complex pedigrees the computational
complexity is critical. We present here a detailed
complexity analysis for the problem of counting the
number of complete consistent genotype
assignments. Our main result is a polynomial time
algorithm for counting the number of complete
consistent assignments for non-looping pedigrees. We
further classify pedigrees according to a number of
natural parameters like the number of generations,
the number of children per individual and the
cardinality of the set of alleles. We show that even
if we assume all these parameters as bounded by
reasonably small constants, the counting problem
becomes computationally hard (\#P-complete) for
looping pedigrees. The border line for counting
problems computable in polynomial time
(i.e. belonging to the class FP) and \#P-hard
problems is completed by showing that even for
general pedigrees with unlimited number of
generations and alleles but with at most one child
per individual and for pedigrees with at most two
generations and two children per individual the
counting problem is in FP.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-27,
author =	 "Zimmer, Pascal",
title =	 "A Calculus for Context-Awareness",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-27",
OPTkey =	 "",
month =	 aug,
note =	 "21~pp",
abstract =	 "In order to answer the challenge of pervasive
computing, we propose a new process calculus, whose
aim is to describe dynamic systems composed of
agents able to move and react differently depending
on their location. This \emph{Context-Aware
Calculus} features a hierarchical structure similar
to mobile ambients, and a generic multi-agent
synchronization mechanism, inspired from the
join-calculus. After general ideas and introduction,
we review the full calculus' syntax and semantics,
as well as some motivating examples, study its
expressiveness, and show how the notion of
computation itself can be made context-dependent",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-26,
author =	 "Rohde, Henning Korsholm",
title =	 "Measuring the Propagation of Information in Partial
Evaluation",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-26",
OPTkey =	 "",
month =	 aug,
note =	 "39~pp",
abstract =	 "We present the first measurement-based analysis of
the information propagated by a partial
evaluator. Our analysis is based on measuring
implementations of string-matching algorithms, based
on the observation that the sequence of character
comparisons accurately reflects maintained
information. Notably, we can easily prove matchers
to be different and we show that they display more
variety and finesse than previously believed. As a
consequence, we are able to pinpoint differences and
inaccuracies in many results previously considered
equivalent.\bibpar Our analysis includes a framework
that lets us obtain string matchers -- notably the
family of Boyer-Moore algorithms -- in a systematic
formalism-independent way from a few
information-propagation primitives. By leveraging
the existing research in string matching, we show
that the landscape of information propagation is
non-trivial in the sense that small changes in
information propagation may dramatically change the
properties of the resulting string matchers. We thus
expect that this work will prove useful as a test
and feedback mechanism for information propagation
in the development of advanced program
transformations, such as GPC or Supercompilation.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-25,
author =	 "Biernacki, Dariusz and Danvy, Olivier",
title =	 "A Simple Proof of a Folklore Theorem about Delimited
Control",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-25",
OPTkey =	 "",
month =	 aug,
note =	 "ii+11~pp. To appear in {\em Journal of Functional
Programming}. This version supersedes BRICS
RS-05-10",
abstract =	 "We formalize and prove the folklore theorem that the
static delimited-control operators shift and reset
can be simulated in terms of the dynamic
delimited-control operators control and prompt. The
proof is based on small-step operational semantics",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-24,
author =	 "Biernacka, Ma{\l}gorzata and Biernacki, Dariusz and
Danvy, Olivier",
title =	 "An Operational Foundation for Delimited
Continuations in the {CPS} Hierarchy",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-24",
OPTkey =	 "",
month =	 aug,
note =	 "iv+43~pp. To appear in the journal {\em Logical
Methods in Computer Science}. This version
supersedes BRICS RS-05-11",
abstract =	 "We present an abstract machine and a reduction
semantics for the $\lambda$-calculus extended with
continuations in the CPS hierarchy. The abstract
machine is derived from an evaluator in
continuation-passing style (CPS); the reduction
semantics (i.e., a small-step operational semantics
with an explicit representation of evaluation
contexts) is constructed from the abstract machine;
and the control operators are the shift and reset
family. At level $n$ of the CPS hierarchy, programs
can use the control operators shift$_i$ and
reset$_i$ for $1 \leq i \leq n$, the evaluator has
$n+1$ layers of continuations, the abstract machine
has $n+1$ layers of control stacks, and the
reduction semantics has $n+1$ layers of evaluation
contexts.\bibpar We also present new applications of
delimited continuations in the CPS hierarchy:
finding list prefixes and normalization by
evaluation for a hierarchical language of units and
products",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-23,
author =	 "Krukow, Karl and Nielsen, Mogens and Sassone,
title =	 "A Framework for Concrete Reputation-Systems",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-23",
OPTkey =	 "",
month =	 jul,
note =	 "48~pp. This is an extended version of a paper to be
presented at ACM CCS'05.",
abstract =	 "In a reputation-based trust-management system,
agents maintain information about the past behaviour
of other agents. This information is used to guide
interaction. However, while trust management is a
component in security decision-making, few existing
reputation-based trust-management systems aim to
provide any formal security-guarantees. We provide a
mathematical framework for a class of simple
reputation-based systems. In these systems,
decisions about interaction are taken based on
policies that are exact requirements on agents' past
histories. We present a basic declarative language,
based on pure-past linear temporal logic, intended
for writing simple policies. While the basic
language is reasonably expressive, we extend it to
encompass more practical policies, including several
known from the literature. A naturally occurring
problem becomes how to efficiently re-evaluate a
policy when new behavioural information is
available. Efficient algorithms for the basic
language are presented and analyzed, and we outline
algorithms for the extended languages as well",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-22,
author =	 "Biernacka, Ma{\l}gorzata and Danvy, Olivier",
title =	 "A Syntactic Correspondence between Context-Sensitive
Calculi and Abstract Machines",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-22",
OPTkey =	 "",
month =	 jul,
note =	 "iv+39~pp",
abstract =	 "We present a systematic construction of
environment-based abstract machines from
context-sensitive calculi of explicit substitutions,
and we illustrate it with a series of calculi and
machines: Krivine's machine with call/cc, the
lambda-mu-calculus, delimited continuations, i/o,
stack inspection, proper tail-recursion, and lazy
evaluation. Most of the machines already exist but
have been obtained independently and are only
indirectly related to the corresponding calculi. All
of the calculi are new and they make it possible to
directly reason about the execution of the
corresponding machines. In connection with the
functional correspondence between evaluation
functions and abstract machines initiated by
Reynolds, the present syntactic correspondence makes
it possible to construct reduction-free
normalization functions out of reduction-based ones,
which was an open problem in the area of
normalization by evaluation.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-21,
author =	 "Gerhardy, Philipp and Kohlenbach, Ulrich",
title =	 "General Logical Metatheorems for Functional
Analysis",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-21",
OPTkey =	 "",
month =	 jul,
note =	 "65~pp",
abstract =	 "In this paper we prove general logical metatheorems
which state that for large classes of theorems and
proofs in (nonlinear) functional analysis it is
possible to extract from the proofs effective bounds
which depend only on very sparse local bounds on
certain parameters. This means that the bounds are
uniform for all parameters meeting these weak local
boundedness conditions. The results vastly
generalize related theorems due to the second author
where the global boundedness of the underlying
metric space (resp. a convex subset of a normed
space) was assumed. Our results treat general
classes of spaces such as metric, hyperbolic,
CAT(0), normed, uniformly convex and inner product
spaces and classes of functions such as
nonexpansive, H{\"o}lder-Lipschitz, uniformly
continuous, bounded and weakly quasi-nonexpansive
ones. We give several applications in the area of
metric fixed point theory. In particular, we show
that the uniformities observed in a number of
recently found effective bounds (by proof theoretic
analysis) can be seen as instances of our general
logical results",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-20,
author =	 "Damg{\aa}rd, Ivan B. and Fehr, Serge and Salvail,
Louis and Schaffner, Christian",
title =	 "Cryptography in the Bounded Quantum Storage Model",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-20",
OPTkey =	 "",
month =	 jul,
note =	 "23~pp",
abstract =	 "We initiate the study of two-party cryptographic
primitives with unconditional security, assuming
that the adversary's {\em quantum} memory is of
bounded size. We show that oblivious transfer and
bit commitment can be implemented in this model
using protocols where honest parties need no quantum
memory, whereas an adversarial player needs quantum
memory of size at least $n/2$ in order to break the
protocol, where $n$ is the number of qubits
transmitted. This is in sharp contrast to the
classical bounded-memory model, where we can only
in honest players' memory size. Our protocols are
efficient, non-interactive and can be implemented
using today's technology. On the technical side, a
new entropic uncertainty relation involving
min-entropy is established",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-19,
author =	 "Aceto, Luca and Fokkink, Willem Jan and
Ing{\'o}lfsd{\'o}ttir, Anna and Luttik, Bas",
title =	 "Finite Equational Bases in Process Algebra: Results
and Open Questions",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-19",
OPTkey =	 "",
month =	 jun,
note =	 "28~pp.",
abstract =	 "Van Glabbeek (1990) presented the linear
time-branching time spectrum of behavioral
equivalences for finitely branching, concrete,
sequential processes. He studied these semantics in
the setting of the basic process algebra BCCSP, and
tried to give finite complete and $\omega$-complete
axiomatizations for them. (An axiomatization $E$ is
$\omega$-complete when an equation can be derived
from $E$ if, and only if, all its closed
instantiations can be derived from $E$.) Obtaining
such axiomatizations in concurrency theory often
turns out to be difficult, even in the setting of
simple languages like BCCSP. This has raised a host
of open questions that have been the subject of
intensive research in recent years. Most of these
questions have been settled over BCCSP, either
positively by giving a finite complete or
$\omega$-complete axiomatization, or negatively by
proving that such an axiomatization does not
exist. Still some open questions remain. This paper
reports on these results, and on the
state-of-the-art on axiomatizations for richer
process algebras, containing constructs like
sequential and parallel composition",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-18,
author =	 "Bogetoft, Peter and Damg{\aa}rd, Ivan B. and
Jakobsen, Thomas and Nielsen, Kurt and Pagter, Jakob
and Toft, Tomas",
title =	 "Secure Computing, Economy, and Trust: A Generic
Solution for Secure Auctions with Real-World
Applications",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-18",
OPTkey =	 "",
month =	 jun,
note =	 "37~pp",
abstract =	 "In this paper we consider the problem of
constructing secure auctions based on techniques
from modern cryptography. We combine knowledge from
economics, cryptography and security engineering and
develop and implement secure auctions for practical
real-world problems.\bibpar In essence this paper is
an overview of the research project SCET---Secure
Computing, Economy, and Trust--- which attempts to
build auctions for real applications using secure
multiparty computation.\bibpar The main
contributions of this project are: A generic setup
for secure evaluation of integer arithmetic
including comparisons; general double auctions
expressed by such operations; a real world double
auction tailored to the complexity and performance
of the basic primitives $+$ and $\leq$; and finally
evidence that our approach is practically feasible
based on experiments with prototypes.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-17,
author =	 "Damg{\aa}rd, Ivan B. and Pedersen, Thomas B. and
Salvail, Louis",
title =	 "A Quantum Cipher with Near Optimal Key-Recycling",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-17",
OPTkey =	 "",
month =	 may,
note =	 "29~pp",
keywords =	 "quantum cryptography, key-recycling, unconditional
security, private-key encryption",
abstract =	 "Assuming an insecure quantum channel and an
authenticated classical channel, we propose an
unconditionally secure scheme for encrypting
classical messages under a shared key, where
attempts to eavesdrop the ciphertext can be
detected. If no eavesdropping is detected, we can
securely re-use the entire key for encrypting new
messages. If eavesdropping is detected, we must
discard a number of key bits corresponding to the
length of the message, but can re-use almost all of
the rest. We show this is essentially optimal. Thus,
provided the adversary does not interfere (too much)
with the quantum channel, we can securely send an
arbitrary number of message bits, independently of
the length of the initial key. Moreover, the
key-recycling mechanism only requires one-bit
feedback. While ordinary quantum key distribution
to obtain a similar functionality, this would need
more rounds of interaction and more communication.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-16,
author =	 "Dariusz Biernacki and Olivier Danvy and Kevin
Millikin",
title =	 "A Dynamic Continuation-Passing Style for Dynamic
Delimited Continuations",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-16",
OPTkey =	 "",
month =	 may,
note =	 "ii+24~pp",
abstract =	 "We present a new abstract machine that accounts for
dynamic delimited continuations. We prove the
correctness of this new abstract machine with
respect to a pre-existing, definitional abstract
machine. Unlike this definitional abstract machine,
the new abstract machine is in defunctionalized
form, which makes it possible to state the
corresponding higher-order evaluator. This evaluator
is in continuation+state passing style and threads a
trail of delimited continuations and a
meta-continuation. Since this style accounts for
dynamic delimited continuations, we refer to it as
dynamic continuation-passing style.'\bibpar We show
that the new machine operates more efficiently than
the definitional one and that the notion of
computation induced by the corresponding evaluator
takes the form of a monad. We also present new
examples and a new simulation of dynamic delimited
continuations in terms of static ones",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-15,
author =	 "Biernacka, Ma{\l}gorzata and Danvy, Olivier",
title =	 "A Concrete Framework for Environment Machines",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-15",
OPTkey =	 "",
month =	 may,
note =	 "ii+25~pp",
abstract =	 "We materialize the common belief that calculi with
explicit substitutions provide an intermediate step
between an abstract specification of substitution in
the lambda-calculus and its concrete
implementations. To this end, we go back to Curien's
original calculus of closures (an early calculus
with explicit substitutions), we extend it minimally
so that it can express one-step reduction
strategies, and we methodically derive a series of
environment machines from the specification of two
one-step reduction strategies for the
lambda-calculus: normal order and applicative
order. The derivation extends Danvy and Nielsen's
refocusing-based construction of abstract machines
with two new steps: one for coalescing two
successive transitions into one, and one for
unfolding a closure into a term and an environment
in the resulting abstract machine. The resulting
environment machines include both the idealized and
the original versions of Krivine's machine,
Felleisen et al.'s CEK machine, and Leroy's Zinc
abstract machine",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-14,
author =	 "Danvy, Olivier and Rohde, Henning Korsholm",
title =	 "On Obtaining the {B}oyer-{M}oore String-Matching
Algorithm by Partial Evaluation",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-14",
OPTkey =	 "",
month =	 apr,
note =	 "ii+8~pp. Superseded by BRICS RS-05-29",
abstract =	 "We present the first derivation of the search phase
of the Boyer-Moore string-matching algorithm by
partial evaluation of an inefficient string
matcher. The derivation hinges on identifying the
improvement, bounded static variation. An
inefficient string matcher incorporating this
binding-time improvement specializes into the search
phase of the Horspool algorithm, which is a
simplified variant of the Boyer-Moore
binding-time improvement with our previous results
yields a new binding-time-improved string matcher
that specializes into the search phase of the
Boyer-Moore algorithm",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-13,
author =	 "Biernacki, Dariusz and Danvy, Olivier and Shan,
Chung-chieh",
title =	 "On the Dynamic Extent of Delimited Continuations",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-13",
OPTkey =	 "",
month =	 apr,
note =	 "ii+32~pp. Extended version of an article to appear in
{\em Information Processing Letters}. Subsumes
BRICS RS-05-2",
abstract =	 "We show that breadth-first traversal exploits the
difference between the static delimited-control
operator shift' (alias S') and the dynamic
delimited-control operator control' (alias
F'). For the last 15 years, this difference has
been repeatedly mentioned in the literature but it
has only been illustrated with one-line toy
examples. Breadth-first traversal fills this vacuum",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-12,
author =	 "Biernacka, Ma{\l}gorzata and Danvy, Olivier and
St{\o}vring, Kristian",
title =	 "Program Extraction from Proofs of Weak Head
Normalization",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-12",
OPTkey =	 "",
month =	 apr,
note =	 "19~pp. Extended version of an article to appear in
the preliminary proceedings of MFPS XXI,
Birmingham, UK, May 2005",
abstract =	 "We formalize two proofs of weak head normalization
for the simply typed lambda-calculus in first-order
minimal logic: one for normal-order reduction, and
one for applicative-order reduction in the object
language. Subsequently we use Kreisel's modified
realizability to extract evaluation algorithms from
the proofs, following Berger; the proofs are based
on Tait-style reducibility predicates, and hence the
extracted algorithms are instances of (weak head)
normalization by evaluation, as already identified
by Coquand and Dybjer",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-11,
author =	 "Biernacka, Ma{\l}gorzata and Biernacki, Dariusz and
Danvy, Olivier",
title =	 "An Operational Foundation for Delimited
Continuations in the {CPS} Hierarchy",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-11",
OPTkey =	 "",
month =	 mar,
note =	 "iii+42~pp. A preliminary version appeared in " #
acmcw04 # ", pages 25--33. This version supersedes
BRICS RS-04-29, but is superseded by BRICS RS-05-24",
abstract =	 "We present an abstract machine and a reduction
semantics for the $\lambda$-calculus extended with
continuations in the CPS hierarchy. The abstract
machine is derived from an evaluator in
continuation-passing style (CPS); the reduction
semantics (i.e., a small-step operational semantics
with an explicit representation of evaluation
contexts) is constructed from the abstract machine;
and the control operators are the shift and reset
family. At level $n$ of the CPS hierarchy, programs
can use the control operators shift$_i$ and
reset$_i$ for $1 \leq i \leq n$, the evaluator has
$n+1$ layers of continuations, the abstract machine
has $n+1$ layers of control stacks, and the
reduction semantics has $n+1$ layers of evaluation
contexts.\bibpar We also present new applications of
delimited continuations in the CPS hierarchy:
finding list prefixes and normalization by
evaluation for a hierarchical language of units and
products",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-10,
author =	 "Biernacki, Dariusz and Danvy, Olivier",
title =	 "A Simple Proof of a Folklore Theorem about Delimited
Control",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-10",
OPTkey =	 "",
month =	 mar,
note =	 "ii+11~pp. Superseded by BRICS RS-05-25",
abstract =	 "We formalize and prove the folklore theorem that the
static delimited-control operators shift and reset
can be simulated in terms of the dynamic
delimited-control operators control and prompt. The
proof is based on a small-step operational semantics
that takes the form of an abstract machine",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-9,
author =	 "Frandsen, Gudmund Skovbjerg and Miltersen, Peter
Bro",
title =	 "Reviewing Bounds on the Circuit Size of the Hardest
Functions",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-9",
OPTkey =	 "",
month =	 mar,
note =	 "6~pp. To appear in {\em Information Processing
Letters}",
abstract =	 "In this paper we review the known bounds for $L(n)$,
the circuit size complexity of the hardest Boolean
function on $n$ input bits. The best known bounds
appear to be $$\frac{2^n}{n}(1+\frac{\log n}{n}-O(\frac{1}{n})) \leq L(n) \leq\frac{2^n}{n}(1+3\frac{\log n}{n}+O(\frac{1}{n}))$$ However, the bounds do not
seem to be explicitly stated in the literature. We
give a simple direct elementary proof of the lower
bound valid for the full binary basis, and we give
an explicit proof of the upper bound valid for the
basis $\{\neg,\wedge,\vee\}$",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-8,
author =	 "Mosses, Peter D.",
title =	 "Exploiting Labels in Structural Operational
Semantics",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-8",
OPTkey =	 "",
month =	 feb,
note =	 "15~pp. Appears in {\em Fundamenta Informaticae},
60:17--31, 2004",
abstract =	 "Structural Operational Semantics (SOS) allows
transitions to be labelled. This is fully exploited
in SOS descriptions of concurrent systems, but
usually not at all in conventional descriptions of
sequential programming languages.\bibpar This paper
shows how the use of labels can provide
significantly simpler and more modular descriptions
of programming languages. However, the full power of
labels is obtained only when the set of labels is
made into a category, as in the recently-proposed
MSOS variant of SOS",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-7,
author =	 "Mosses, Peter D.",
title =	 "Modular Structural Operational Semantics",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-7",
OPTkey =	 "",
month =	 feb,
note =	 "46~pp. Appears in {\em Journal of Logic and Algebraic
Programming}, 60--61:195--228, 2004 ",
keywords =	 "structural operational semantics, SOS, modularity, MSOS",
abstract =	 "Modular SOS (MSOS) is a variant of conventional
Structural Operational Semantics (SOS). Using MSOS,
the transition rules for each construct of a
programming language can be given incrementally,
once and for all, and do not need reformulation when
further constructs are added to the language. MSOS
thus provides an exceptionally high degree of
modularity in language descriptions, removing a
shortcoming of the original SOS framework.\bibpar
After sketching the background and reviewing the
main features of SOS, the paper explains the crucial
differences between SOS and MSOS, and illustrates
how MSOS descriptions are written. It also discusses
standard notions of semantic equivalence based on
MSOS\@. An appendix shows how the illustrative MSOS
rules given in the paper would be formulated in
conventional SOS\@.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-6,
author =	 "Krukow, Karl and Twigg, Andrew",
title =	 "Distributed Approximation of Fixed-Points in Trust
Structures",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-6",
OPTkey =	 "",
month =	 feb,
note =	 "41~pp",
abstract =	 "Recently, Carbone, Nielsen and Sassone introduced
the trust-structure framework; a semantic model for
trust-management in global-scale distributed
systems. The framework is based on the notion of
trust structures; a set of trust-levels'' ordered
by two distinct partial orderings. In the model, a
unique global trust-state is defined as the least
fixed-point of a collection of local policies
assigning trust-levels to the entities of the
system. However, the framework is a purely
denotational model: it gives precise meaning to the
global trust-state of a system, but without
specifying a way to compute this abstract
mathematical object.\bibpar This paper complements
q                  the denotational model of trust structures with
operational techniques. It is shown how the least
fixed-point can be computed using a simple,
totally-asynchronous distributed algorithm. Two
efficient protocols for approximating the least
fixed-point are provided, enabling sound reasoning
about the global trust-state without computing the
exact fixed-point. Finally, dynamic algorithms are
presented for safe reuse of information between
computations, in face of dynamic trust-policy
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-5,
author =	 "Dariusz Biernacki and Olivier Danvy and Kevin
Millikin",
title =	 "A Dynamic Continuation-Passing Style for Dynamic
Delimited Continuations (Preliminary Version)",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-5",
OPTkey =	 "",
month =	 feb,
note =	 "ii+16~pp. Superseded by BRICS RS-05-16",
abstract =	 "We present a new abstract machine that accounts for
dynamic delimited continuations. We prove the
correctness of this new abstract machine with
respect to a definitional abstract machine. Unlike
this definitional abstract machine, the new abstract
machine is in defunctionalized form, which makes it
possible to state the corresponding higher-order
evaluator. This evaluator is in continuation+state
passing style, and threads a trail of delimited
continuations and a meta-continuation. Since this
style accounts for dynamic delimited continuations,
we refer to it as dynamic continuation-passing
style.'\bibpar We illustrate that the new machine is
more efficient than the definitional one, and we
show that the notion of computation induced by the
corresponding evaluator takes the form of a monad",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-4,
author =	 "Filinski, Andrzej and Rohde, Henning Korsholm",
title =	 "Denotational Aspects of Untyped Normalization by
Evaluation",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-4",
OPTkey =	 "",
month =	 feb,
note =	 "51~pp. Extended version of an article to appear in the
FOSSACS 2004 special issue of RAIRO, {\em
Theoretical Informatics and Applications}",
abstract =	 "We show that the standard
normalization-by-evaluation construction for the
simply-typed $\lambda_{\beta\eta}$-calculus has a
natural counterpart for the untyped
$\lambda_\beta$-calculus, with the central
type-indexed logical relation replaced by a
recursively defined'' \emph{invariant relation},
in the style of Pitts. In fact, the construction can
be seen as generalizing a computational-adequacy
argument for an untyped, call-by-name language to
normalization instead of evaluation.\bibpar In the
untyped setting, not all terms have normal forms, so
the normalization function is necessarily
partial. We establish its correctness in the senses
of \emph{soundness} (the output term, if any, is in
normal form and $\beta$-equivalent to the input
term); \emph{identification} ($\beta$-equivalent
terms are mapped to the same result); and
\emph{completeness} (the function is defined for all
terms that do have normal forms). We also show how
the semantic construction enables a simple yet
formal correctness proof for the normalization
algorithm, expressed as a functional program in an
ML-like call-by-value language.\bibpar Finally, we
generalize the construction to produce an infinitary
variant of normal forms, namely \emph{B\"ohm
trees}. We show that the three-part characterization
of correctness, as well as the proofs, extend
naturally to this generalization.",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-3,
author =	 "Danvy, Olivier and Goldberg, Mayer",
title =	 "There and Back Again",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-3",
OPTkey =	 "",
month =	 jan,
note =	 "iii+16~pp. Extended version of an article to appear
in {\em Fundamenta Informaticae}. This version
supersedes BRICS RS-02-12",
abstract =	 "We present a programming pattern where a recursive
function defined over a data structure traverses
another data structure at return time. The idea is
that the recursive calls get us there' by
traversing the first data structure and the returns
get us back again' while traversing the second data
structure. We name this programming pattern of
traversing a data structure at call time and another
data structure at return time There And Back
Again'' (TABA).\bibpar The TABA pattern directly
applies to computing symbolic convolutions and to
multiplying polynomials. It also blends well with
other programming patterns such as dynamic
programming and traversing a list at double
speed. We illustrate TABA and dynamic programming
with Catalan numbers. We illustrate TABA and
traversing a list at double speed with palindromes
and we obtain a novel solution to this traditional
exercise. Finally, through a variety of tree
traversals, we show how to apply TABA to other data
structures than lists.\bibpar A TABA-based function
written in direct style makes full use of an
ALGOL-like control stack and needs no heap
allocation. Conversely, in a TABA-based function
written in continuation-passing style and
recursively defined over a data structure (traversed
at call time), the continuation acts as an iterator
over a second data structure (traversed at return
time). In general, the TABA pattern saves one from
accumulating intermediate data structures at call
time",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-2,
author =	 "Biernacki, Dariusz and Danvy, Olivier",
title =	 "On the Dynamic Extent of Delimited Continuations",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-2",
OPTkey =	 "",
month =	 jan,
note =	 "ii+30~pp",
abstract =	 "We show that breadth-first traversal exploits the
difference between the static delimited-control
operator shift (alias S) and the dynamic
delimited-control operator control (alias F). For
the last 15 years, this difference has been
repeatedly mentioned in the literature but it has
only been illustrated with one-line toy
vacuum.\bibpar We also point out where static
delimited continuations naturally give rise to the
notion of control stack whereas dynamic delimited
continuations can be made to account for a notion of
control queue.'",
OPTannote =	 ""
}

@TechReport{BRICS-RS-05-1,
author =	 "Goldberg, Mayer",
title =	 "On the Recursive Enumerability of Fixed-Point
Combinators",
institution =	 brics,
year =	 2005,
type =	 rs,
number =	 "RS-05-1",
OPTkey =	 "",
month =	 jan,
note =	 "7~pp. Superseedes BRICS report RS-04-25",
abstract =	 "We show that the set of fixed-point combinators
forms a recursively-enumerable subset of a larger
set of terms we call non-standard fixed-point
combinators. These terms are observationally
equivalent to fixed-point combinators in any
computable context, but the set of on-standard
fixed-point combinators is not recursively
enumerable",
`