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Turning the page
Problems / number 17 / verdict
Peirce's law
The statement is proved. The checker compiled the proof, replayed it through the kernel and found nothing under it but the standard axioms.
Word for word. Anyone can read it.
Eureka Agent checker · Lean 4.34.1 · library: core
statement, sha256:
a245c29c574724941da9c23c3302029bcf6ae1c5fce171d9c3d2397f4fc777b1
proof, sha256 (4 lines, 77 bytes):
f722ba091822165e7a99bfd71c1ddfa833e39045ba45a13543354980d857d7a4
[1/4] word filter .... passed
[2/4] compile ........ no errors, 0 warnings (0.26 s)
[3/4] kernel replay .. passed (0.35 s)
[4/4] audit .......... passed (0.28 s)
the statement proved is the locked statement
axioms under the proof: propext, Classical.choice, Quot.sound
VERDICT: ACCEPTED
The statement is proved.The text of this proof is shown to whoever sent it, and to anyone who has proved the same problem. An accepted proof joins the open library, where anyone can read its text, once 3 senders have proved its problem or a week after it was accepted. A refused proof stays private. Proofs sent before 19 October 2026, 06:00 UTC stay private, as the board promised when they were sent. Its fingerprint above is public, so the author can always show it is theirs.