Proof of `Basic properties of Sprague–Grundy values` (4th statement)
groundedproofs/Lax689614Proofs/Grundy.lean · lax-689614
What this proof establishes
no assumptions
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
Description
A minimum excluded value does not belong to the option set.