Theorem lmodvsubadd

Description: Relationship between vector subtraction and addition. ( hvsubadd analog.) (Contributed by NM, 31-Mar-2014) (Revised by Mario Carneiro, 19-Jun-2014)

	Ref	Expression
Hypotheses	lmod4.v	⊢ 𝑉 = ( Base ‘ 𝑊 )
	lmod4.p	⊢ + = ( +g ‘ 𝑊 )
	lmodvaddsub4.m	⊢ − = ( -g ‘ 𝑊 )
Assertion	lmodvsubadd	⊢ ( ( 𝑊 ∈ LMod ∧ ( 𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉 ) ) → ( ( 𝐴 − 𝐵 ) = 𝐶 ↔ ( 𝐵 + 𝐶 ) = 𝐴 ) )

Proof

Step	Hyp	Ref	Expression
1		lmod4.v	⊢ 𝑉 = ( Base ‘ 𝑊 )
2		lmod4.p	⊢ + = ( +g ‘ 𝑊 )
3		lmodvaddsub4.m	⊢ − = ( -g ‘ 𝑊 )
4		lmodabl	⊢ ( 𝑊 ∈ LMod → 𝑊 ∈ Abel )
5	1 2 3	ablsubadd	⊢ ( ( 𝑊 ∈ Abel ∧ ( 𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉 ) ) → ( ( 𝐴 − 𝐵 ) = 𝐶 ↔ ( 𝐵 + 𝐶 ) = 𝐴 ) )
6	4 5	sylan	⊢ ( ( 𝑊 ∈ LMod ∧ ( 𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑉 ∧ 𝐶 ∈ 𝑉 ) ) → ( ( 𝐴 − 𝐵 ) = 𝐶 ↔ ( 𝐵 + 𝐶 ) = 𝐴 ) )