reduction_exists.py: every disk with k>=1 (and every irreducible disk)
has a Phi-NON-INCREASING vertex removal (|Phi(D-v)| <= |Phi(D)|), 100%
over thousands of disks -- so induction to the k=0 base case is viable.
BUT the clean set-inclusion Phi(D-v) subset Phi(D) holds for only ~8%, so
the size step cannot be proved by "re-inserting v loses no sequence"; it
needs a genuine cardinality injection between non-nested sets.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
didericis
d7c93cf2c2