UNDECIDABLE STATEMENT
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Harvey Friedman's TREE(3)
Peano Arithmetic / Weak Set Theories
The function TREE(n) grows so fast that proving TREE(3) is finite requires axioms far beyond PA. The number itself is incomprehensibly large.
SIGNIFICANCE
A concrete, finitely-stated combinatorial fact whose proof escapes most standard axiomatic systems.
Neither provable nor refutable · rotates daily