diff --git a/library/data/finset/card.lean b/library/data/finset/card.lean index 84d53c78b..4c330fbef 100644 --- a/library/data/finset/card.lean +++ b/library/data/finset/card.lean @@ -106,11 +106,10 @@ finset.induction_on s theorem inj_on_of_card_image_eq {f : A → B} {s : finset A} : card (image f s) = card s → inj_on f (ts s) := finset.induction_on s - (by intro H; xrewrite to_set_empty; apply inj_on_empty) + (by intro H; rewrite to_set_empty; apply inj_on_empty) (begin intro a s' Ha IH, - rewrite [image_insert, card_insert_of_not_mem Ha], - xrewrite [to_set_insert], + rewrite [image_insert, card_insert_of_not_mem Ha, to_set_insert], assume H1 : card (insert (f a) (image f s')) = card s' + 1, show inj_on f (set.insert a (ts s')), from decidable.by_cases