Metamath Proof Explorer


Theorem dprdf

Description: The function S is a family of subgroups. (Contributed by Mario Carneiro, 25-Apr-2016)

Ref Expression
Assertion dprdf G dom DProd S S : dom S SubGrp G

Proof

Step Hyp Ref Expression
1 reldmdprd Rel dom DProd
2 1 brrelex2i G dom DProd S S V
3 2 dmexd G dom DProd S dom S V
4 eqid dom S = dom S
5 eqid Cntz G = Cntz G
6 eqid 0 G = 0 G
7 eqid mrCls SubGrp G = mrCls SubGrp G
8 5 6 7 dmdprd dom S V dom S = dom S G dom DProd S G Grp S : dom S SubGrp G x dom S y dom S x S x Cntz G S y S x mrCls SubGrp G S dom S x = 0 G
9 3 4 8 sylancl G dom DProd S G dom DProd S G Grp S : dom S SubGrp G x dom S y dom S x S x Cntz G S y S x mrCls SubGrp G S dom S x = 0 G
10 9 ibi G dom DProd S G Grp S : dom S SubGrp G x dom S y dom S x S x Cntz G S y S x mrCls SubGrp G S dom S x = 0 G
11 10 simp2d G dom DProd S S : dom S SubGrp G