scratch

§ Proof That There Is a TM Whose Halting Is Independent of ZFC

created 2022-09-25
  • Start by assuming that ZFC is consistent.
  • Consider a TM which enumerates proofs in ZFC (ie, sequents if we want to use sequent calculus), looking for a sequent that proves the inoncsistency of ZFC.
  • If this TM halts, then it has proven inconsistency of ZFC, which contradicts our hypothesis.
  • If it does not halt, then this means that we have proven the consistency of ZFC in ZFC, which contradicts Godel's incompleteness theorem.
  • Thus, it is independent of ZFC whether TM M halts or not.
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