Database
BASIC CATEGORY THEORY
Arrows (disjointified hom-sets)
df-homa
Metamath Proof Explorer
Description: Definition of the hom-set extractor for arrows, which tags the morphisms
of the underlying hom-set with domain and codomain, which can then be
extracted using df-doma and df-coda . (Contributed by FL , 6-May-2007) (Revised by Mario Carneiro , 11-Jan-2017)
Ref
Expression
Assertion
df-homa
⊢ Homa = ( 𝑐 ∈ Cat ↦ ( 𝑥 ∈ ( ( Base ‘ 𝑐 ) × ( Base ‘ 𝑐 ) ) ↦ ( { 𝑥 } × ( ( Hom ‘ 𝑐 ) ‘ 𝑥 ) ) ) )
Detailed syntax breakdown
Step
Hyp
Ref
Expression
0
choma
⊢ Homa
1
vc
⊢ 𝑐
2
ccat
⊢ Cat
3
vx
⊢ 𝑥
4
cbs
⊢ Base
5
1
cv
⊢ 𝑐
6
5 4
cfv
⊢ ( Base ‘ 𝑐 )
7
6 6
cxp
⊢ ( ( Base ‘ 𝑐 ) × ( Base ‘ 𝑐 ) )
8
3
cv
⊢ 𝑥
9
8
csn
⊢ { 𝑥 }
10
chom
⊢ Hom
11
5 10
cfv
⊢ ( Hom ‘ 𝑐 )
12
8 11
cfv
⊢ ( ( Hom ‘ 𝑐 ) ‘ 𝑥 )
13
9 12
cxp
⊢ ( { 𝑥 } × ( ( Hom ‘ 𝑐 ) ‘ 𝑥 ) )
14
3 7 13
cmpt
⊢ ( 𝑥 ∈ ( ( Base ‘ 𝑐 ) × ( Base ‘ 𝑐 ) ) ↦ ( { 𝑥 } × ( ( Hom ‘ 𝑐 ) ‘ 𝑥 ) ) )
15
1 2 14
cmpt
⊢ ( 𝑐 ∈ Cat ↦ ( 𝑥 ∈ ( ( Base ‘ 𝑐 ) × ( Base ‘ 𝑐 ) ) ↦ ( { 𝑥 } × ( ( Hom ‘ 𝑐 ) ‘ 𝑥 ) ) ) )
16
0 15
wceq
⊢ Homa = ( 𝑐 ∈ Cat ↦ ( 𝑥 ∈ ( ( Base ‘ 𝑐 ) × ( Base ‘ 𝑐 ) ) ↦ ( { 𝑥 } × ( ( Hom ‘ 𝑐 ) ‘ 𝑥 ) ) ) )