Metamath Proof Explorer


Theorem h1datom

Description: A 1-dimensional subspace is an atom. (Contributed by NM, 22-Jul-2001) (New usage is discouraged.)

Ref Expression
Assertion h1datom ACBABA=BA=0

Proof

Step Hyp Ref Expression
1 sseq1 A=ifACA0ABifACA0B
2 eqeq1 A=ifACA0A=BifACA0=B
3 eqeq1 A=ifACA0A=0ifACA0=0
4 2 3 orbi12d A=ifACA0A=BA=0ifACA0=BifACA0=0
5 1 4 imbi12d A=ifACA0ABA=BA=0ifACA0BifACA0=BifACA0=0
6 sneq B=ifBB0B=ifBB0
7 6 fveq2d B=ifBB0B=ifBB0
8 7 fveq2d B=ifBB0B=ifBB0
9 8 sseq2d B=ifBB0ifACA0BifACA0ifBB0
10 8 eqeq2d B=ifBB0ifACA0=BifACA0=ifBB0
11 10 orbi1d B=ifBB0ifACA0=BifACA0=0ifACA0=ifBB0ifACA0=0
12 9 11 imbi12d B=ifBB0ifACA0BifACA0=BifACA0=0ifACA0ifBB0ifACA0=ifBB0ifACA0=0
13 h0elch 0C
14 13 elimel ifACA0C
15 ifhvhv0 ifBB0
16 14 15 h1datomi ifACA0ifBB0ifACA0=ifBB0ifACA0=0
17 5 12 16 dedth2h ACBABA=BA=0