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APAL
2008
95views more  APAL 2008»
13 years 11 months ago
The associated sheaf functor theorem in algebraic set theory
Abstract. We prove a version of the associated sheaf functor theorem in Algebraic Set Theory. The proof is established working within a Heyting pretopos equipped with a system of s...
Nicola Gambino
APAL
2008
63views more  APAL 2008»
13 years 11 months ago
A standard model of Peano arithmetic with no conservative elementary extension
The principal result of this paper answers a long-standing question in the model theory of arithmetic [KS, Question 7] by showing that there exists an uncountable arithmetically cl...
Ali Enayat
APAL
2008
49views more  APAL 2008»
13 years 11 months ago
A note on a theorem of Ax
Piotr Kowalski
APAL
2008
102views more  APAL 2008»
13 years 11 months ago
Partial automorphism semigroups
Abstract. We study the relationship between algebraic structures and their inverse semigroups of partial automorphisms. We consider a variety of classes of natural structures inclu...
Jennifer Chubb, Valentina S. Harizanov, Andrei S. ...
APAL
2008
62views more  APAL 2008»
13 years 11 months ago
The upward closure of a perfect thin class
There is a perfect thin 0 1 class whose upward closure in the Turing degrees has full measure (and indeed contains every 2-random degree.) Thus, in the Muchnik lattice of 0 1 class...
Rod Downey, Noam Greenberg, Joseph S. Miller
APAL
2008
79views more  APAL 2008»
13 years 11 months ago
Parameter-free polymorphic types
Consider the following restriction of the polymorphically typed lambda calculus ("System F"). All quantifications are parameter free. In other words, in every universal ...
Klaus Aehlig
APAL
2008
112views more  APAL 2008»
13 years 11 months ago
A domain model characterising strong normalisation
Building on previous work by Coquand and Spiwack [8] we construct a strict domaintheoretic model for the untyped -calculus with pattern matching and term rewriting which has the p...
Ulrich Berger
APAL
2008
59views more  APAL 2008»
13 years 11 months ago
Introduction to Turing categories
J. Robin B. Cockett, Pieter J. W. Hofstra