Metamath Proof Explorer


Definition df-homa

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 ) ) ) )