Metamath Proof Explorer


Theorem sylow2b

Description: Sylow's second theorem. Any P -group H is a subgroup of a conjugated P -group K of order P ^ n || ( #X ) with n maximal. This is usually stated under the assumption that K is a Sylow subgroup, but we use a slightly different definition, whose equivalence to this one requires this theorem. This is part of Metamath 100 proof #72. (Contributed by Mario Carneiro, 18-Jan-2015)

Ref Expression
Hypotheses sylow2b.x ⊢ X = Base G
sylow2b.xf ⊢ φ → X ∈ Fin
sylow2b.h ⊢ φ → H ∈ SubGrp ⁡ G
sylow2b.k ⊢ φ → K ∈ SubGrp ⁡ G
sylow2b.a ⊢ + ˙ = + G
sylow2b.hp ⊢ φ → P pGrp G ↾ 𝑠 H
sylow2b.kn ⊢ φ → K = P P pCnt X
sylow2b.d ⊢ - ˙ = - G
Assertion sylow2b ⊢ φ → ∃ g ∈ X H ⊆ ran ⁡ x ∈ K ⟼ g + ˙ x - ˙ g

Proof

Step Hyp Ref Expression
1 sylow2b.x ⊢ X = Base G
2 sylow2b.xf ⊢ φ → X ∈ Fin
3 sylow2b.h ⊢ φ → H ∈ SubGrp ⁡ G
4 sylow2b.k ⊢ φ → K ∈ SubGrp ⁡ G
5 sylow2b.a ⊢ + ˙ = + G
6 sylow2b.hp ⊢ φ → P pGrp G ↾ 𝑠 H
7 sylow2b.kn ⊢ φ → K = P P pCnt X
8 sylow2b.d ⊢ - ˙ = - G
9 eqid ⊢ G ~ QG K = G ~ QG K
10 oveq2 ⊢ s = z → u + ˙ s = u + ˙ z
11 10 cbvmptv ⊢ s ∈ v ⟼ u + ˙ s = z ∈ v ⟼ u + ˙ z
12 oveq1 ⊢ u = x → u + ˙ z = x + ˙ z
13 12 mpteq2dv ⊢ u = x → z ∈ v ⟼ u + ˙ z = z ∈ v ⟼ x + ˙ z
14 11 13 eqtrid ⊢ u = x → s ∈ v ⟼ u + ˙ s = z ∈ v ⟼ x + ˙ z
15 14 rneqd ⊢ u = x → ran ⁡ s ∈ v ⟼ u + ˙ s = ran ⁡ z ∈ v ⟼ x + ˙ z
16 mpteq1 ⊢ v = y → z ∈ v ⟼ x + ˙ z = z ∈ y ⟼ x + ˙ z
17 16 rneqd ⊢ v = y → ran ⁡ z ∈ v ⟼ x + ˙ z = ran ⁡ z ∈ y ⟼ x + ˙ z
18 15 17 cbvmpov ⊢ u ∈ H , v ∈ X / G ~ QG K ⟼ ran ⁡ s ∈ v ⟼ u + ˙ s = x ∈ H , y ∈ X / G ~ QG K ⟼ ran ⁡ z ∈ y ⟼ x + ˙ z
19 1 2 3 4 5 9 18 6 7 8 sylow2blem3 ⊢ φ → ∃ g ∈ X H ⊆ ran ⁡ x ∈ K ⟼ g + ˙ x - ˙ g