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A CLASSICAL MODAL THEORY OF LAWLESS SEQUENCES

Published online by Cambridge University Press:  09 March 2023

ETHAN BRAUER*
Affiliation:
DEPARTMENT OF PHILOSOPHY LINGNAN UNIVERSITY 8 CASTLE PEAK RD. TUEN MUN, HONG KONG E-mail: eebrauer@gmail.com

Abstract

Free choice sequences play a key role in the intuitionistic theory of the continuum and especially in the theorems of intuitionistic analysis that conflict with classical analysis, leading many classical mathematicians to reject the concept of a free choice sequence. By treating free choice sequences as potentially infinite objects, however, they can be comfortably situated alongside classical analysis, allowing a rapprochement of these two mathematical traditions. Building on recent work on the modal analysis of potential infinity, I formulate a modal theory of the free choice sequences known as lawless sequences. Intrinsically well-motivated axioms for lawless sequences are added to a background theory of classical second-order arithmetic, leading to a theory I call $MC_{LS}$. This theory interprets the standard intuitionistic theory of lawless sequences and is conservative over the classical background theory.

Type
Articles
Copyright
© The Author(s), 2023. Published by Cambridge University Press on behalf of The Association for Symbolic Logic

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