Fibrations and Calculi of Fractions

Jaap van Oosten

November 1994


Given a fibration tex2html_wrap_inline21 and a class tex2html_wrap_inline23 of arrows of tex2html_wrap_inline25, one can construct the free fibration (on tex2html_wrap_inline27 over tex2html_wrap_inline25 such that all reindexing functors over elements of tex2html_wrap_inline23 are equivalences. In this work I give an explicit construction of this, and study its properties. For example, the construction preserves the property of being fibrewise discrete, and it commutes up to equivalence with fibrewise exact completions. I show that mathematically interesting situations are examples of this construction. In particular, subtoposes of the effective topos are treated.

Available as PostScript, PDF, DVI.


Last modified: 2003-06-08 by webmaster.