Metamath Proof Explorer


Theorem fh4i

Description: Variation of the Foulis-Holland Theorem. (Contributed by NM, 16-Jan-2005) (New usage is discouraged.)

Ref Expression
Hypotheses fh1.1 AC
fh1.2 BC
fh1.3 CC
fh1.4 A𝐶B
fh1.5 A𝐶C
Assertion fh4i BAC=BABC

Proof

Step Hyp Ref Expression
1 fh1.1 AC
2 fh1.2 BC
3 fh1.3 CC
4 fh1.4 A𝐶B
5 fh1.5 A𝐶C
6 1 choccli AC
7 2 choccli BC
8 3 choccli CC
9 1 2 4 cmcm3ii A𝐶B
10 6 2 9 cmcm2ii A𝐶B
11 1 3 5 cmcm3ii A𝐶C
12 6 3 11 cmcm2ii A𝐶C
13 6 7 8 10 12 fh2i BAC=BABC
14 1 3 chdmm1i AC=AC
15 14 ineq2i BAC=BAC
16 2 1 chdmj1i BA=BA
17 2 3 chdmj1i BC=BC
18 16 17 oveq12i BABC=BABC
19 13 15 18 3eqtr4ri BABC=BAC
20 2 1 chjcli BAC
21 2 3 chjcli BCC
22 20 21 chdmm1i BABC=BABC
23 1 3 chincli ACC
24 2 23 chdmj1i BAC=BAC
25 19 22 24 3eqtr4i BABC=BAC
26 2 23 chjcli BACC
27 20 21 chincli BABCC
28 26 27 chcon3i BAC=BABCBABC=BAC
29 25 28 mpbir BAC=BABC