Metamath Proof Explorer


Theorem hpgcom

Description: The half-plane relation commutes. Theorem 9.12 of Schwabhauser p. 72. (Contributed by Thierry Arnoux, 4-Mar-2020)

Ref Expression
Hypotheses hpgid.p 𝑃 = ( Base ‘ 𝐺 )
hpgid.i 𝐼 = ( Itv ‘ 𝐺 )
hpgid.l 𝐿 = ( LineG ‘ 𝐺 )
hpgid.g ( 𝜑𝐺 ∈ TarskiG )
hpgid.d ( 𝜑𝐷 ∈ ran 𝐿 )
hpgid.a ( 𝜑𝐴𝑃 )
hpgid.o 𝑂 = { ⟨ 𝑎 , 𝑏 ⟩ ∣ ( ( 𝑎 ∈ ( 𝑃𝐷 ) ∧ 𝑏 ∈ ( 𝑃𝐷 ) ) ∧ ∃ 𝑡𝐷 𝑡 ∈ ( 𝑎 𝐼 𝑏 ) ) }
hpgcom.b ( 𝜑𝐵𝑃 )
hpgcom.1 ( 𝜑𝐴 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐵 )
Assertion hpgcom ( 𝜑𝐵 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐴 )

Proof

Step Hyp Ref Expression
1 hpgid.p 𝑃 = ( Base ‘ 𝐺 )
2 hpgid.i 𝐼 = ( Itv ‘ 𝐺 )
3 hpgid.l 𝐿 = ( LineG ‘ 𝐺 )
4 hpgid.g ( 𝜑𝐺 ∈ TarskiG )
5 hpgid.d ( 𝜑𝐷 ∈ ran 𝐿 )
6 hpgid.a ( 𝜑𝐴𝑃 )
7 hpgid.o 𝑂 = { ⟨ 𝑎 , 𝑏 ⟩ ∣ ( ( 𝑎 ∈ ( 𝑃𝐷 ) ∧ 𝑏 ∈ ( 𝑃𝐷 ) ) ∧ ∃ 𝑡𝐷 𝑡 ∈ ( 𝑎 𝐼 𝑏 ) ) }
8 hpgcom.b ( 𝜑𝐵𝑃 )
9 hpgcom.1 ( 𝜑𝐴 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐵 )
10 ancom ( ( 𝐴 𝑂 𝑐𝐵 𝑂 𝑐 ) ↔ ( 𝐵 𝑂 𝑐𝐴 𝑂 𝑐 ) )
11 10 a1i ( 𝜑 → ( ( 𝐴 𝑂 𝑐𝐵 𝑂 𝑐 ) ↔ ( 𝐵 𝑂 𝑐𝐴 𝑂 𝑐 ) ) )
12 11 rexbidv ( 𝜑 → ( ∃ 𝑐𝑃 ( 𝐴 𝑂 𝑐𝐵 𝑂 𝑐 ) ↔ ∃ 𝑐𝑃 ( 𝐵 𝑂 𝑐𝐴 𝑂 𝑐 ) ) )
13 1 2 3 7 4 5 6 8 hpgbr ( 𝜑 → ( 𝐴 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐵 ↔ ∃ 𝑐𝑃 ( 𝐴 𝑂 𝑐𝐵 𝑂 𝑐 ) ) )
14 1 2 3 7 4 5 8 6 hpgbr ( 𝜑 → ( 𝐵 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐴 ↔ ∃ 𝑐𝑃 ( 𝐵 𝑂 𝑐𝐴 𝑂 𝑐 ) ) )
15 12 13 14 3bitr4d ( 𝜑 → ( 𝐴 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐵𝐵 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐴 ) )
16 9 15 mpbid ( 𝜑𝐵 ( ( hpG ‘ 𝐺 ) ‘ 𝐷 ) 𝐴 )