Proof of `Finite linear images and their uniform-law density bounds` (3rd statement)
groundedproofs/Lax342547Proofs/FiniteLinearLaw.lean · lax-342547
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
Translation does not change fiber cardinalities. Each nonempty fiber has at most the kernel cardinality, and rank-nullity gives the reciprocal power of two for every lower bound on the image dimension.