4 papers
Two random constructions inside lacunary sets
Stefan Neuwirth
We study the relationship between the growth rate of an integer sequence and harmonic and functional properties of the corresponding sequence of characters. In particular we show t…
Azumaya algebras and Barr Theorem
Thierry Coquand, Henri Lombardi, Stefan Neuwirth
We study etale topology and the notion of Azumaya algebra over a commutative ring constructively. As an application of the syntactic version of Barr's Theorem, we show the equivale…
Constructive theory of ordinals
Thierry Coquand, Henri Lombardi, Stefan Neuwirth
In Chapter 3 of his Notes on constructive mathematics, Martin-L{ö}f describes recursively constructed ordinals. He gives a constructively acceptable version of Kleene's computable…
An introduction to Lorenzen's "Algebraic and logistic investigations on free lattices" (1951)
Thierry Coquand, Henri Lombardi, Stefan Neuwirth
Lorenzen's ``Algebraische und logistische Untersuchungen über freie Verbände'' appeared in 1951 in The Journal of Symbolic Logic. These ``Investigations'' have immediately been r…