Encyclopedia Mathematics Mathematics Godel Theorems Structural From Rs Limitative Result Count

ARTICLE 2 claims 2 theorems

Mathematics Godel Theorems Structural From Rs Limitative Result Count

A machine-checked theorem counts five classic limitative results of logic, and nothing more.

A bare counting fact

The five landmark limitative results of 20th-century mathematical logic are Gödel's first incompleteness theorem (1931), Gödel's second incompleteness theorem (1931), Tarski's undefinability of truth (1933), Church's undecidability of the Entscheidungsproblem (1936), and Turing's halting problem (1936). Each states a fundamental boundary on what formal systems can prove, define, or decide. A machine-checked library of formal theorems records these five results as a five-constructor inductive type, a way of defining a collection by listing its possible forms.

The declaration limitativeResult_count proves that this type has exactly five elements. The proof is a direct computation: the theorem states Fintype.card LimitativeResult = 5, and the machine checks it by deciding the case. This is a bare counting fact. It does not prove any of the five theorems themselves, nor does it analyze their content. The names attached to the five constructors carry the same logical weight as labels on a five-element set.

In Recognition Science, this counting fact plugs into dimension-counting bridges elsewhere in the framework, where a configuration dimension of five is used. The declaration also packages the count into a structure called GodelTheoremsCert, a certificate that the five results form a five-element finite type.

What the declaration does not claim is essential. It is not a claim that Recognition Science evades any of these five results. None of the five constructors carries a proof that the corresponding theorem fails to apply to the framework. The names are labels, not theorems. For the honest analysis of how Gödel I and Tarski's undefinability interact with Recognition Science, the framework points to a separate paper that argues the recovered arithmetic inherits Gödel I just as Peano arithmetic does.

THEOREM limitativeResult_count · IndisputableMonolith/Mathematics/GodelTheoremsStructuralFromRS.lean
theorem limitativeResult_count :
    Fintype.card LimitativeResult = 5 := by decide
THEOREM LimitativeResult · IndisputableMonolith/Mathematics/GodelTheoremsStructuralFromRS.lean
inductive LimitativeResult where
  | godelFirst
  | godelSecond
  | tarskiUndefinability
  | churchUndecidability
  | turingHalting
  deriving DecidableEq, Repr, BEq, Fintype

What this page does not claim

The declaration proves none of the five limitative theorems themselves. The declaration says nothing about whether Recognition Science is subject to or exempt from any of the five results. The declaration does not analyze the content or implications of the five theorems.

Verify this page

Every tagged claim above names its theorem. To check one yourself rather than trust this page, elaborate the source module with Lean 4 and audit its axiom basis:

$ lake env lean IndisputableMonolith/Mathematics/GodelTheoremsStructuralFromRS.lean
expected axiom basis: [propext, Classical.choice, Quot.sound] (the Lean kernel's standard three; no RS-specific axioms)

A page whose claims cannot be reproduced this way does not ship. In production, every anchor links to the exact declaration in the public source release, and this block carries the build receipt for the page itself.

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