VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY
Autor(a) principal: | |
---|---|
Data de Publicação: | 2021 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10362/131978 |
Resumo: | Kreisel's conjecture is the statement: if, for all n ∈ ℕ, PA ⊢ksteps φ(n), then PA ⊢ ∀x.φ(x). For a theory of arithmetic T, given a recursive function h, T ⊢≤h φ holds if there is a proof of φ in T whose code is at most h(#φ). This notion depends on the underlying coding. PhT(x) is a provability predicate for ⊢≤h in T. It is shown that there exists a sentence φ and a total recursive function h such that T ⊢≤h PrT(⌈PrT (⌈φ⌉) → φ⌉), but T ⊢/≤h φ, where PrTstands for the standard provability predicate in T. This statement is related to a conjecture by Montagna. Also variants and weakenings of Kreisel's conjecture are studied. By use of reexion principles, one can obtain a theory ThΓ that extends T such that a version of Kreisel's conjecture holds: given a recursive function h and φ(x) a Γ- formula (where Γ is an arbitrarily fixed class of formulas) such that, for all n ∈ N, T ⊢≤h φ(n), then ThΓ⊢ ∀x.φ(x). Derivability conditions are studied for a theory to statisfy the following implication: if T ⊢ ∀x.PhT(pφ(x)q), then T ⊢ ∀x.φ(x). This corresponds to an arithmetization of Kreisel's conjecture. It is shown that, for certain theories, there exists a function h such that ⊢k steps ⊆ ⊢≤h. |
id |
RCAP_499a53fb9ee96836f5464ae183dfbaca |
---|---|
oai_identifier_str |
oai:run.unl.pt:10362/131978 |
network_acronym_str |
RCAP |
network_name_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository_id_str |
|
spelling |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITYPhilosophyLogicKreisel's conjecture is the statement: if, for all n ∈ ℕ, PA ⊢ksteps φ(n), then PA ⊢ ∀x.φ(x). For a theory of arithmetic T, given a recursive function h, T ⊢≤h φ holds if there is a proof of φ in T whose code is at most h(#φ). This notion depends on the underlying coding. PhT(x) is a provability predicate for ⊢≤h in T. It is shown that there exists a sentence φ and a total recursive function h such that T ⊢≤h PrT(⌈PrT (⌈φ⌉) → φ⌉), but T ⊢/≤h φ, where PrTstands for the standard provability predicate in T. This statement is related to a conjecture by Montagna. Also variants and weakenings of Kreisel's conjecture are studied. By use of reexion principles, one can obtain a theory ThΓ that extends T such that a version of Kreisel's conjecture holds: given a recursive function h and φ(x) a Γ- formula (where Γ is an arbitrarily fixed class of formulas) such that, for all n ∈ N, T ⊢≤h φ(n), then ThΓ⊢ ∀x.φ(x). Derivability conditions are studied for a theory to statisfy the following implication: if T ⊢ ∀x.PhT(pφ(x)q), then T ⊢ ∀x.φ(x). This corresponds to an arithmetization of Kreisel's conjecture. It is shown that, for certain theories, there exists a function h such that ⊢k steps ⊆ ⊢≤h.CMA - Centro de Matemática e AplicaçõesRUNSantos, Paulo GuilhermeKahle, Reinhard2022-02-01T03:39:42Z2021-122021-12-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10362/131978eng1079-8986PURE: 35844533https://doi.org/10.1017/bsl.2021.68info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-10T16:04:47ZPortal AgregadorONG |
dc.title.none.fl_str_mv |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY |
title |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY |
spellingShingle |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY Santos, Paulo Guilherme Philosophy Logic |
title_short |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY |
title_full |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY |
title_fullStr |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY |
title_full_unstemmed |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY |
title_sort |
VARIANTS of KREISEL'S CONJECTURE on A NEW NOTION of PROVABILITY |
author |
Santos, Paulo Guilherme |
author_facet |
Santos, Paulo Guilherme Kahle, Reinhard |
author_role |
author |
author2 |
Kahle, Reinhard |
author2_role |
author |
dc.contributor.none.fl_str_mv |
CMA - Centro de Matemática e Aplicações RUN |
dc.contributor.author.fl_str_mv |
Santos, Paulo Guilherme Kahle, Reinhard |
dc.subject.por.fl_str_mv |
Philosophy Logic |
topic |
Philosophy Logic |
description |
Kreisel's conjecture is the statement: if, for all n ∈ ℕ, PA ⊢ksteps φ(n), then PA ⊢ ∀x.φ(x). For a theory of arithmetic T, given a recursive function h, T ⊢≤h φ holds if there is a proof of φ in T whose code is at most h(#φ). This notion depends on the underlying coding. PhT(x) is a provability predicate for ⊢≤h in T. It is shown that there exists a sentence φ and a total recursive function h such that T ⊢≤h PrT(⌈PrT (⌈φ⌉) → φ⌉), but T ⊢/≤h φ, where PrTstands for the standard provability predicate in T. This statement is related to a conjecture by Montagna. Also variants and weakenings of Kreisel's conjecture are studied. By use of reexion principles, one can obtain a theory ThΓ that extends T such that a version of Kreisel's conjecture holds: given a recursive function h and φ(x) a Γ- formula (where Γ is an arbitrarily fixed class of formulas) such that, for all n ∈ N, T ⊢≤h φ(n), then ThΓ⊢ ∀x.φ(x). Derivability conditions are studied for a theory to statisfy the following implication: if T ⊢ ∀x.PhT(pφ(x)q), then T ⊢ ∀x.φ(x). This corresponds to an arithmetization of Kreisel's conjecture. It is shown that, for certain theories, there exists a function h such that ⊢k steps ⊆ ⊢≤h. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-12 2021-12-01T00:00:00Z 2022-02-01T03:39:42Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10362/131978 |
url |
http://hdl.handle.net/10362/131978 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
1079-8986 PURE: 35844533 https://doi.org/10.1017/bsl.2021.68 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
|
repository.mail.fl_str_mv |
|
_version_ |
1777303055770845184 |