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Database
BASIC CATEGORY THEORY
Categories
Monomorphisms and epimorphisms
df-epi
Metamath Proof Explorer
Description: Function returning the epimorphisms of the category c . JFM CAT_1
def. 11. (Contributed by FL , 8-Aug-2008) (Revised by Mario Carneiro , 2-Jan-2017)
Ref
Expression
Assertion
df-epi
⊢ Epi = c ∈ Cat ⟼ tpos Mono ⁡ oppCat ⁡ c
Detailed syntax breakdown
Step
Hyp
Ref
Expression
0
cepi
class Epi
1
vc
setvar c
2
ccat
class Cat
3
cmon
class Mono
4
coppc
class oppCat
5
1
cv
setvar c
6
5 4
cfv
class oppCat ⁡ c
7
6 3
cfv
class Mono ⁡ oppCat ⁡ c
8
7
ctpos
class tpos Mono ⁡ oppCat ⁡ c
9
1 2 8
cmpt
class c ∈ Cat ⟼ tpos Mono ⁡ oppCat ⁡ c
10
0 9
wceq
wff Epi = c ∈ Cat ⟼ tpos Mono ⁡ oppCat ⁡ c