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| author |  Jasper Hugunin <jasper@hashplex.com> | 2017-12-11 12:07:47 +0900 |
|---|---|---|
| committer |  GitHub <noreply@github.com> | 2017-12-11 12:07:47 +0900 |
| commit | 882c692d91bd56a2534ac862b8d557b529aaae54 (patch) | |
| tree | 0cb6c8b76eb25ed754562762d0c5e8f2b0b3f7a4 /theories | |
| parent | 94468c0572eb50ea39a07f9a9ed93bc7a8a2f4b6 (diff) | |
Axiom-free proof of eta expansion.
Diffstat (limited to 'theories')
| -rw-r--r-- | theories/Logic/FunctionalExtensionality.v | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/theories/Logic/FunctionalExtensionality.v b/theories/Logic/FunctionalExtensionality.v index ac95ddd0c..82b04d132 100644 --- a/theories/Logic/FunctionalExtensionality.v +++ b/theories/Logic/FunctionalExtensionality.v @@ -221,13 +221,12 @@ Tactic Notation "extensionality" "in" hyp(H) := (* If we [subst H], things break if we already have another equation of the form [_ = H] *) destruct Heq; rename H_out into H. -(** Eta expansion follows from extensionality. *) +(** Eta expansion is built into Coq. *) Lemma eta_expansion_dep {A} {B : A -> Type} (f : forall x : A, B x) : f = fun x => f x. Proof. intros. - extensionality x. reflexivity. Qed. |