Metamath Proof Explorer


Definition df-ida

Description: Definition of the identity arrow, which is just the identity morphism tagged with its domain and codomain. (Contributed by FL, 26-Oct-2007) (Revised by Mario Carneiro, 11-Jan-2017)

Ref Expression
Assertion df-ida Ida = ( 𝑐 ∈ Cat ↦ ( 𝑥 ∈ ( Base ‘ 𝑐 ) ↦ ⟨ 𝑥 , 𝑥 , ( ( Id ‘ 𝑐 ) ‘ 𝑥 ) ⟩ ) )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cida Ida
1 vc 𝑐
2 ccat Cat
3 vx 𝑥
4 cbs Base
5 1 cv 𝑐
6 5 4 cfv ( Base ‘ 𝑐 )
7 3 cv 𝑥
8 ccid Id
9 5 8 cfv ( Id ‘ 𝑐 )
10 7 9 cfv ( ( Id ‘ 𝑐 ) ‘ 𝑥 )
11 7 7 10 cotp 𝑥 , 𝑥 , ( ( Id ‘ 𝑐 ) ‘ 𝑥 ) ⟩
12 3 6 11 cmpt ( 𝑥 ∈ ( Base ‘ 𝑐 ) ↦ ⟨ 𝑥 , 𝑥 , ( ( Id ‘ 𝑐 ) ‘ 𝑥 ) ⟩ )
13 1 2 12 cmpt ( 𝑐 ∈ Cat ↦ ( 𝑥 ∈ ( Base ‘ 𝑐 ) ↦ ⟨ 𝑥 , 𝑥 , ( ( Id ‘ 𝑐 ) ‘ 𝑥 ) ⟩ ) )
14 0 13 wceq Ida = ( 𝑐 ∈ Cat ↦ ( 𝑥 ∈ ( Base ‘ 𝑐 ) ↦ ⟨ 𝑥 , 𝑥 , ( ( Id ‘ 𝑐 ) ‘ 𝑥 ) ⟩ ) )