Proof of `Wagner's theorem`
conditional — 2 open assumptionsproofs/Lax68Proofs/Wagner.lean · lax-68
What this proof establishes
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
Kuratowski's theorem characterizes finite planar graphs by the absence of the two topological obstructions. The Kuratowski-Wagner bridge identifies those topological obstructions with the corresponding minor obstructions.