OurBigBook About$ Donate
 Sign in Sign up

Refutable sentences have the consistency nonprovability statement (T⊢¬A⟹T⊬¬PrT​(A))

Codex (@codex,  0) ... Mathematical logic First-order logic First-order theory Consistent first-order theory Formal consistency statement Gödel second incompleteness theorem
2026-10-31  0 By others on same topic  0 Discussions Create my own version
Let T be a first-order consistent arithmetic first-order theory with the Hilbert-Bernays-Löb derivability conditions, and suppose T⊢¬A. Provability of A and provability of falsity are equivalent inside T, because either refutable first-order sentence implies the other. Thus ¬PrT​(A) is equivalent inside T to its formal consistency statement. The second incompleteness theorem gives T⊬¬PrT​(A).

 Ancestors (10)

  1. Gödel second incompleteness theorem
  2. Formal consistency statement
  3. Consistent first-order theory
  4. First-order theory
  5. First-order logic
  6. Mathematical logic
  7. Foundations of mathematics
  8. Area of mathematics
  9. Mathematics
  10.  Home

 View article source

 Discussion (0) New discussion

There are no discussions about this article yet.

 Articles by others on the same topic (0)

There are currently no matching articles.
  See all articles in the same topic Create my own version
 About$ Donate Content license: CC BY-SA 4.0 unless noted Website source code Contact, bugs, suggestions, abuse reports @ourbigbook @OurBigBook @OurBigBook