Metamath Proof Explorer


Theorem motco

Description: The composition of two motions is a motion. (Contributed by Thierry Arnoux, 15-Dec-2019)

Ref Expression
Hypotheses ismot.p ⊢ P = Base G
ismot.m ⊢ - ˙ = dist ⁡ G
motgrp.1 ⊢ φ → G ∈ V
motco.2 ⊢ φ → F ∈ G Ismt G
motco.3 ⊢ φ → H ∈ G Ismt G
Assertion motco ⊢ φ → F ∘ H ∈ G Ismt G

Proof

Step Hyp Ref Expression
1 ismot.p ⊢ P = Base G
2 ismot.m ⊢ - ˙ = dist ⁡ G
3 motgrp.1 ⊢ φ → G ∈ V
4 motco.2 ⊢ φ → F ∈ G Ismt G
5 motco.3 ⊢ φ → H ∈ G Ismt G
6 1 2 3 4 motf1o ⊢ φ → F : P ⟶ 1-1 onto P
7 1 2 3 5 motf1o ⊢ φ → H : P ⟶ 1-1 onto P
8 f1oco ⊢ F : P ⟶ 1-1 onto P ∧ H : P ⟶ 1-1 onto P → F ∘ H : P ⟶ 1-1 onto P
9 6 7 8 syl2anc ⊢ φ → F ∘ H : P ⟶ 1-1 onto P
10 f1of ⊢ H : P ⟶ 1-1 onto P → H : P ⟶ P
11 7 10 syl ⊢ φ → H : P ⟶ P
12 11 adantr ⊢ φ ∧ a ∈ P ∧ b ∈ P → H : P ⟶ P
13 simprl ⊢ φ ∧ a ∈ P ∧ b ∈ P → a ∈ P
14 fvco3 ⊢ H : P ⟶ P ∧ a ∈ P → F ∘ H ⁡ a = F ⁡ H ⁡ a
15 12 13 14 syl2anc ⊢ φ ∧ a ∈ P ∧ b ∈ P → F ∘ H ⁡ a = F ⁡ H ⁡ a
16 simprr ⊢ φ ∧ a ∈ P ∧ b ∈ P → b ∈ P
17 fvco3 ⊢ H : P ⟶ P ∧ b ∈ P → F ∘ H ⁡ b = F ⁡ H ⁡ b
18 12 16 17 syl2anc ⊢ φ ∧ a ∈ P ∧ b ∈ P → F ∘ H ⁡ b = F ⁡ H ⁡ b
19 15 18 oveq12d ⊢ φ ∧ a ∈ P ∧ b ∈ P → F ∘ H ⁡ a - ˙ F ∘ H ⁡ b = F ⁡ H ⁡ a - ˙ F ⁡ H ⁡ b
20 3 adantr ⊢ φ ∧ a ∈ P ∧ b ∈ P → G ∈ V
21 12 13 ffvelcdmd ⊢ φ ∧ a ∈ P ∧ b ∈ P → H ⁡ a ∈ P
22 12 16 ffvelcdmd ⊢ φ ∧ a ∈ P ∧ b ∈ P → H ⁡ b ∈ P
23 4 adantr ⊢ φ ∧ a ∈ P ∧ b ∈ P → F ∈ G Ismt G
24 1 2 20 21 22 23 motcgr ⊢ φ ∧ a ∈ P ∧ b ∈ P → F ⁡ H ⁡ a - ˙ F ⁡ H ⁡ b = H ⁡ a - ˙ H ⁡ b
25 5 adantr ⊢ φ ∧ a ∈ P ∧ b ∈ P → H ∈ G Ismt G
26 1 2 20 13 16 25 motcgr ⊢ φ ∧ a ∈ P ∧ b ∈ P → H ⁡ a - ˙ H ⁡ b = a - ˙ b
27 19 24 26 3eqtrd ⊢ φ ∧ a ∈ P ∧ b ∈ P → F ∘ H ⁡ a - ˙ F ∘ H ⁡ b = a - ˙ b
28 27 ralrimivva ⊢ φ → ∀ a ∈ P ∀ b ∈ P F ∘ H ⁡ a - ˙ F ∘ H ⁡ b = a - ˙ b
29 1 2 ismot ⊢ G ∈ V → F ∘ H ∈ G Ismt G ↔ F ∘ H : P ⟶ 1-1 onto P ∧ ∀ a ∈ P ∀ b ∈ P F ∘ H ⁡ a - ˙ F ∘ H ⁡ b = a - ˙ b
30 3 29 syl ⊢ φ → F ∘ H ∈ G Ismt G ↔ F ∘ H : P ⟶ 1-1 onto P ∧ ∀ a ∈ P ∀ b ∈ P F ∘ H ⁡ a - ˙ F ∘ H ⁡ b = a - ˙ b
31 9 28 30 mpbir2and ⊢ φ → F ∘ H ∈ G Ismt G