Metamath Proof Explorer


Theorem h1de2ci

Description: Membership in 1-dimensional subspace. All members are collinear with the generating vector. (Contributed by NM, 21-Jul-2001) (Revised by Mario Carneiro, 15-May-2014) (New usage is discouraged.)

Ref Expression
Hypothesis h1de2ct.1 B
Assertion h1de2ci A B x A = x B

Proof

Step Hyp Ref Expression
1 h1de2ct.1 B
2 snssi B B
3 occl B B C
4 1 2 3 mp2b B C
5 4 choccli B C
6 5 cheli A B A
7 hvmulcl x B x B
8 1 7 mpan2 x x B
9 eleq1 A = x B A x B
10 8 9 syl5ibrcom x A = x B A
11 10 rexlimiv x A = x B A
12 eleq1 A = if A A 0 A B if A A 0 B
13 eqeq1 A = if A A 0 A = x B if A A 0 = x B
14 13 rexbidv A = if A A 0 x A = x B x if A A 0 = x B
15 12 14 bibi12d A = if A A 0 A B x A = x B if A A 0 B x if A A 0 = x B
16 ifhvhv0 if A A 0
17 16 1 h1de2ctlem if A A 0 B x if A A 0 = x B
18 15 17 dedth A A B x A = x B
19 6 11 18 pm5.21nii A B x A = x B