eng
episciences.org
Discrete Mathematics & Theoretical Computer Science
1365-8050
2007-01-01
Vol. 9 no. 2
10.46298/dmtcs.392
392
journal article
Baire and automata
Pierre Simonnet
Benoit Cagnard
In his thesis Baire defined functions of Baire class 1. A function f is of Baire class 1 if it is the pointwise limit of a sequence of continuous functions. Baire proves the following theorem. A function f is not of class 1 if and only if there exists a closed nonempty set F such that the restriction of f to F has no point of continuity. We prove the automaton version of this theorem. An ω-rational function is not of class 1 if and only if there exists a closed nonempty set F recognized by a Büchi automaton such that the restriction of f to F has no point of continuity. This gives us the opportunity for a discussion on Hausdorff's analysis of Δ°2, ordinals, transfinite induction and some applications of computer science.
https://dmtcs.episciences.org/392/pdf
[INFO.INFO-DM] Computer Science [cs]/Discrete Mathematics [cs.DM]