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refactor(library/data/finset/card): remove unnecessary xrewrite

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We can use the default 'rewrite' tactic after the commits pushed today.
This commit is contained in:
Leonardo de Moura 2015-06-10 18:46:16 -07:00
parent dc8768627c
commit 1b5d1136d9
1 changed files with 2 additions and 3 deletions
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library/data/finset/card.lean
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@ -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