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Theorem

Loeb's Theorem

Logic and Foundations

In mathematical logic, Loeb's theorem states that in Peano arithmetic, or any formal system including it, for any formula P, if it is provable that 'if P is provable then P is true' then P is itself provable. It is named after Martin Hugo Loeb, who formulated it in 1955, and connects to Curry's paradox. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/

Facts
Statement
In Peano arithmetic, or any formal system that includes it, for any formula P, if it is provable that the sentence P is provable implies P is true, then P is itself provable. 1
Proof Year
1955 1
Connections

In Branch

Sources
1. Loeb's theorem (Wikipedia)
Wikimedia Foundation
  • lead section, first paragraph
    In mathematical logic, Löb's theorem states that in Peano arithmetic (PA) (or any formal system including PA), for any formula P, if it is provable in PA that "if P is provable in PA then P is true", then P is provable in PA.
  • lead section, third paragraph
    Löb's theorem is named for Martin Hugo Löb, who formulated it in 1955.
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