Metamath Proof Explorer


Theorem ispautN

Description: The predictate "is a projective automorphism." (Contributed by NM, 26-Jan-2012) (New usage is discouraged.)

Ref Expression
Hypotheses pautset.s 𝑆 = ( PSubSp ‘ 𝐾 )
pautset.m 𝑀 = ( PAut ‘ 𝐾 )
Assertion ispautN ( 𝐾𝐵 → ( 𝐹𝑀 ↔ ( 𝐹 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) ) ) )

Proof

Step Hyp Ref Expression
1 pautset.s 𝑆 = ( PSubSp ‘ 𝐾 )
2 pautset.m 𝑀 = ( PAut ‘ 𝐾 )
3 1 2 pautsetN ( 𝐾𝐵𝑀 = { 𝑓 ∣ ( 𝑓 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝑓𝑥 ) ⊆ ( 𝑓𝑦 ) ) ) } )
4 3 eleq2d ( 𝐾𝐵 → ( 𝐹𝑀𝐹 ∈ { 𝑓 ∣ ( 𝑓 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝑓𝑥 ) ⊆ ( 𝑓𝑦 ) ) ) } ) )
5 f1of ( 𝐹 : 𝑆1-1-onto𝑆𝐹 : 𝑆𝑆 )
6 1 fvexi 𝑆 ∈ V
7 fex ( ( 𝐹 : 𝑆𝑆𝑆 ∈ V ) → 𝐹 ∈ V )
8 5 6 7 sylancl ( 𝐹 : 𝑆1-1-onto𝑆𝐹 ∈ V )
9 8 adantr ( ( 𝐹 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) ) → 𝐹 ∈ V )
10 f1oeq1 ( 𝑓 = 𝐹 → ( 𝑓 : 𝑆1-1-onto𝑆𝐹 : 𝑆1-1-onto𝑆 ) )
11 fveq1 ( 𝑓 = 𝐹 → ( 𝑓𝑥 ) = ( 𝐹𝑥 ) )
12 fveq1 ( 𝑓 = 𝐹 → ( 𝑓𝑦 ) = ( 𝐹𝑦 ) )
13 11 12 sseq12d ( 𝑓 = 𝐹 → ( ( 𝑓𝑥 ) ⊆ ( 𝑓𝑦 ) ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) )
14 13 bibi2d ( 𝑓 = 𝐹 → ( ( 𝑥𝑦 ↔ ( 𝑓𝑥 ) ⊆ ( 𝑓𝑦 ) ) ↔ ( 𝑥𝑦 ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) ) )
15 14 2ralbidv ( 𝑓 = 𝐹 → ( ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝑓𝑥 ) ⊆ ( 𝑓𝑦 ) ) ↔ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) ) )
16 10 15 anbi12d ( 𝑓 = 𝐹 → ( ( 𝑓 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝑓𝑥 ) ⊆ ( 𝑓𝑦 ) ) ) ↔ ( 𝐹 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) ) ) )
17 9 16 elab3 ( 𝐹 ∈ { 𝑓 ∣ ( 𝑓 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝑓𝑥 ) ⊆ ( 𝑓𝑦 ) ) ) } ↔ ( 𝐹 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) ) )
18 4 17 bitrdi ( 𝐾𝐵 → ( 𝐹𝑀 ↔ ( 𝐹 : 𝑆1-1-onto𝑆 ∧ ∀ 𝑥𝑆𝑦𝑆 ( 𝑥𝑦 ↔ ( 𝐹𝑥 ) ⊆ ( 𝐹𝑦 ) ) ) ) )