From d27936801b2997af16814e2879c8bdf6f4eb7bcc Mon Sep 17 00:00:00 2001 From: Cyril Cohen Date: Mon, 18 Nov 2019 18:22:20 +0100 Subject: Adding `inj_compr` lemma in ssrfun. --- plugins/ssr/ssrfun.v | 3 +++ 1 file changed, 3 insertions(+) diff --git a/plugins/ssr/ssrfun.v b/plugins/ssr/ssrfun.v index b8affba541..dd847169b9 100644 --- a/plugins/ssr/ssrfun.v +++ b/plugins/ssr/ssrfun.v @@ -675,6 +675,9 @@ Proof. by move=> fK injf' x; apply: injf'. Qed. Lemma inj_comp : injective f -> injective h -> injective (f \o h). Proof. by move=> injf injh x y /injf; apply: injh. Qed. +Lemma inj_compr : injective (f \o h) -> injective h. +Proof. by move=> injfh x y /(congr1 f) /injfh. Qed. + Lemma can_comp f' h' : cancel f f' -> cancel h h' -> cancel (f \o h) (h' \o f'). Proof. by move=> fK hK x; rewrite /= fK hK. Qed. -- cgit v1.2.3 From 75ea93f63050a05a5b20124c17eb18a98e66fd6a Mon Sep 17 00:00:00 2001 From: Cyril Cohen Date: Tue, 19 Nov 2019 10:38:07 +0100 Subject: added changelog entry --- doc/changelog/06-ssreflect/11136-inj_compr.rst | 1 + 1 file changed, 1 insertion(+) create mode 100644 doc/changelog/06-ssreflect/11136-inj_compr.rst diff --git a/doc/changelog/06-ssreflect/11136-inj_compr.rst b/doc/changelog/06-ssreflect/11136-inj_compr.rst new file mode 100644 index 0000000000..9c118ce0b5 --- /dev/null +++ b/doc/changelog/06-ssreflect/11136-inj_compr.rst @@ -0,0 +1 @@ +- added lemma inj_compr (`#11136 `_, by Cyril Cohen). -- cgit v1.2.3 From 9832c2a4714fc594f159e277f65b0d388ff643d7 Mon Sep 17 00:00:00 2001 From: Cyril Cohen Date: Thu, 21 Nov 2019 02:07:33 +0100 Subject: Taking @Zimmi48's comment into account Co-Authored-By: Théo Zimmermann --- doc/changelog/06-ssreflect/11136-inj_compr.rst | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/doc/changelog/06-ssreflect/11136-inj_compr.rst b/doc/changelog/06-ssreflect/11136-inj_compr.rst index 9c118ce0b5..b546fcde6b 100644 --- a/doc/changelog/06-ssreflect/11136-inj_compr.rst +++ b/doc/changelog/06-ssreflect/11136-inj_compr.rst @@ -1 +1,2 @@ -- added lemma inj_compr (`#11136 `_, by Cyril Cohen). +- Added lemma :g:`inj_compr` to :g:`ssr.ssrfun` + (`#11136 `_, by Cyril Cohen). -- cgit v1.2.3