WikiLeanRecent changes · Proposals · Flags · Stats · About

Diff — Diffeomorphism

Revision #1149 → #2439 · back to history

modifiedMilnor's exotic 7-spherec9b3987c483d
FieldFrom #1149To #2439
noteThe existence of an exotic 7-sphere is stated as a `proof_wanted` in Mathlib: a manifold homeomorphic to S^7 but with no diffeomorphism to S^7. The proof is not yet provided.The existence of an exotic 7-sphere is stated as a `proof_wanted` in Mathlib: a manifold homeomorphic to S^7 but with no diffeomorphism to S^7. The proof is not yet provided. (Mathlib declares this as `proof_wanted` — stated, not yet proven.)
provenanceaiai-moderated
statuspartialnot_formalized
modifiedExotic R^4: uncountably many non-diffeomorphic smooth structures4729e82d6965
FieldFrom #1149To #2439
noteMathlib states the existence of a small exotic R^4 as a `proof_wanted`, but not the uncountability of exotic smooth structures. The full result is far from formalized.Mathlib states the existence of a small exotic R^4 as a `proof_wanted`, but not the uncountability of exotic smooth structures. The full result is far from formalized. (Mathlib declares this as `proof_wanted` — stated, not yet proven.)
provenanceaiai-moderated
statuspartialnot_formalized