Theorem cgrrflx

Description: Reflexivity law for congruence. Theorem 2.1 of Schwabhauser p. 27. (Contributed by Scott Fenton, 12-Jun-2013)

	Ref	Expression
Assertion	cgrrflx	⊢ ( ( 𝑁 ∈ ℕ ∧ 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) ∧ 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) ) → ⟨ 𝐴 , 𝐵 ⟩ Cgr ⟨ 𝐴 , 𝐵 ⟩ )

Proof

Step	Hyp	Ref	Expression
1		simp1	⊢ ( ( 𝑁 ∈ ℕ ∧ 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) ∧ 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) ) → 𝑁 ∈ ℕ )
2		simp3	⊢ ( ( 𝑁 ∈ ℕ ∧ 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) ∧ 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) ) → 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) )
3		simp2	⊢ ( ( 𝑁 ∈ ℕ ∧ 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) ∧ 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) ) → 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) )
4		axcgrrflx	⊢ ( ( 𝑁 ∈ ℕ ∧ 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) ∧ 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) ) → ⟨ 𝐵 , 𝐴 ⟩ Cgr ⟨ 𝐴 , 𝐵 ⟩ )
5	4	3com23	⊢ ( ( 𝑁 ∈ ℕ ∧ 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) ∧ 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) ) → ⟨ 𝐵 , 𝐴 ⟩ Cgr ⟨ 𝐴 , 𝐵 ⟩ )
6	1 2 3 3 2 3 2 5 5	cgrtr4d	⊢ ( ( 𝑁 ∈ ℕ ∧ 𝐴 ∈ ( 𝔼 ‘ 𝑁 ) ∧ 𝐵 ∈ ( 𝔼 ‘ 𝑁 ) ) → ⟨ 𝐴 , 𝐵 ⟩ Cgr ⟨ 𝐴 , 𝐵 ⟩ )