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Main Authors: Cioffo, Cipriano Junior, Maietti, Maria Emilia, Maschio, Samuele
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.19239
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author Cioffo, Cipriano Junior
Maietti, Maria Emilia
Maschio, Samuele
author_facet Cioffo, Cipriano Junior
Maietti, Maria Emilia
Maschio, Samuele
contents We describe the fibrational structure of sets within the predicative variant $\mathbf{pEff}$ of Hyland's Effective Topos $\mathbf{Eff}$ previously introduced in Feferman's predicative theory of non-iterative fixpoints $\widehat{ID_1}$. Our structural analysis can be carried out in constructive and predicative variants of $\mathbf{Eff}$ within extensions of Aczel's Constructive Zermelo-Fraenkel Set Theory. All this shows that the full subcategory of discrete objects of Hyland's Effective topos $\mathbf{Eff}$ contains already a fibred predicative topos validating the formal Church's thesis, even when both are formalized in a constructive metatheory.
format Preprint
id arxiv_https___arxiv_org_abs_2411_19239
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fibred sets within a predicative and constructive effective topos
Cioffo, Cipriano Junior
Maietti, Maria Emilia
Maschio, Samuele
Logic
We describe the fibrational structure of sets within the predicative variant $\mathbf{pEff}$ of Hyland's Effective Topos $\mathbf{Eff}$ previously introduced in Feferman's predicative theory of non-iterative fixpoints $\widehat{ID_1}$. Our structural analysis can be carried out in constructive and predicative variants of $\mathbf{Eff}$ within extensions of Aczel's Constructive Zermelo-Fraenkel Set Theory. All this shows that the full subcategory of discrete objects of Hyland's Effective topos $\mathbf{Eff}$ contains already a fibred predicative topos validating the formal Church's thesis, even when both are formalized in a constructive metatheory.
title Fibred sets within a predicative and constructive effective topos
topic Logic
url https://arxiv.org/abs/2411.19239