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short exact sequences

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This commit is contained in:
Egbert Rijke 2017-01-26 17:44:22 -05:00
parent e59f0adedf
commit 2d995b0347
1 changed files with 1 additions and 1 deletions
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algebra/quotient_group.hlean
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@ -382,7 +382,7 @@ definition ab_group_first_iso_thm {A B : AbGroup} (f : A →g B)
exact is_surjective_kernel_quotient_to_image f
end
definition codomain_surjection_is_quotient (A B : AbGroup) (f : A →g B)( H : is_surjective f)
definition codomain_surjection_is_quotient {A B : AbGroup} (f : A →g B)( H : is_surjective f)
: quotient_ab_group (kernel_subgroup f) ≃g B :=
begin
exact (ab_group_first_iso_thm f) ⬝g (iso_surjection_ab_image_incl f H)