Metamath Proof Explorer


Theorem ringccofvalALTV

Description: Composition in the category of rings. (Contributed by AV, 14-Feb-2020) (New usage is discouraged.)

Ref Expression
Hypotheses ringcbasALTV.c C = RingCatALTV U
ringcbasALTV.b B = Base C
ringcbasALTV.u φ U V
ringccoALTV.o · ˙ = comp C
Assertion ringccofvalALTV φ · ˙ = v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f

Proof

Step Hyp Ref Expression
1 ringcbasALTV.c C = RingCatALTV U
2 ringcbasALTV.b B = Base C
3 ringcbasALTV.u φ U V
4 ringccoALTV.o · ˙ = comp C
5 1 2 3 ringcbasALTV φ B = U Ring
6 eqid Hom C = Hom C
7 1 2 3 6 ringchomfvalALTV φ Hom C = x B , y B x RingHom y
8 eqidd φ v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f = v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f
9 1 3 5 7 8 ringcvalALTV φ C = Base ndx B Hom ndx Hom C comp ndx v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f
10 9 fveq2d φ comp C = comp Base ndx B Hom ndx Hom C comp ndx v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f
11 2 fvexi B V
12 sqxpexg B V B × B V
13 11 12 ax-mp B × B V
14 13 11 mpoex v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f V
15 catstr Base ndx B Hom ndx Hom C comp ndx v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f Struct 1 15
16 ccoid comp = Slot comp ndx
17 snsstp3 comp ndx v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f Base ndx B Hom ndx Hom C comp ndx v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f
18 15 16 17 strfv v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f V v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f = comp Base ndx B Hom ndx Hom C comp ndx v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f
19 14 18 ax-mp v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f = comp Base ndx B Hom ndx Hom C comp ndx v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f
20 10 4 19 3eqtr4g φ · ˙ = v B × B , z B g 2 nd v RingHom z , f 1 st v RingHom 2 nd v g f