Theorem ramcl2

Description: The Ramsey number is either a nonnegative integer or plus infinity. (Contributed by Mario Carneiro, 20-Apr-2015) (Revised by AV, 14-Sep-2020)

	Ref	Expression
Assertion	ramcl2	⊢ ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) → ( 𝑀 Ramsey 𝐹 ) ∈ ( ℕ0 ∪ { +∞ } ) )

Proof

Step	Hyp	Ref	Expression
1		eqid	⊢ ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) = ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } )
2		eqid	⊢ { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } = { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) }
3	1 2	ramcl2lem	⊢ ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) → ( 𝑀 Ramsey 𝐹 ) = if ( { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } = ∅ , +∞ , inf ( { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } , ℝ , < ) ) )
4		iftrue	⊢ ( { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } = ∅ → if ( { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } = ∅ , +∞ , inf ( { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } , ℝ , < ) ) = +∞ )
5	3 4	sylan9eq	⊢ ( ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) ∧ { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } = ∅ ) → ( 𝑀 Ramsey 𝐹 ) = +∞ )
6		ssun2	⊢ { +∞ } ⊆ ( ℕ0 ∪ { +∞ } )
7		pnfex	⊢ +∞ ∈ V
8	7	snss	⊢ ( +∞ ∈ ( ℕ0 ∪ { +∞ } ) ↔ { +∞ } ⊆ ( ℕ0 ∪ { +∞ } ) )
9	6 8	mpbir	⊢ +∞ ∈ ( ℕ0 ∪ { +∞ } )
10	5 9	eqeltrdi	⊢ ( ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) ∧ { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } = ∅ ) → ( 𝑀 Ramsey 𝐹 ) ∈ ( ℕ0 ∪ { +∞ } ) )
11		ssun1	⊢ ℕ0 ⊆ ( ℕ0 ∪ { +∞ } )
12	1 2	ramtcl2	⊢ ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) → ( ( 𝑀 Ramsey 𝐹 ) ∈ ℕ0 ↔ { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } ≠ ∅ ) )
13	12	biimpar	⊢ ( ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) ∧ { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } ≠ ∅ ) → ( 𝑀 Ramsey 𝐹 ) ∈ ℕ0 )
14	11 13	sselid	⊢ ( ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) ∧ { 𝑛 ∈ ℕ0 ∣ ∀ 𝑠 ( 𝑛 ≤ ( ♯ ‘ 𝑠 ) → ∀ 𝑓 ∈ ( 𝑅 ↑m ( 𝑠 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ) ∃ 𝑐 ∈ 𝑅 ∃ 𝑥 ∈ 𝒫 𝑠 ( ( 𝐹 ‘ 𝑐 ) ≤ ( ♯ ‘ 𝑥 ) ∧ ( 𝑥 ( 𝑎 ∈ V , 𝑖 ∈ ℕ0 ↦ { 𝑏 ∈ 𝒫 𝑎 ∣ ( ♯ ‘ 𝑏 ) = 𝑖 } ) 𝑀 ) ⊆ ( ◡ 𝑓 “ { 𝑐 } ) ) ) } ≠ ∅ ) → ( 𝑀 Ramsey 𝐹 ) ∈ ( ℕ0 ∪ { +∞ } ) )
15	10 14	pm2.61dane	⊢ ( ( 𝑀 ∈ ℕ0 ∧ 𝑅 ∈ 𝑉 ∧ 𝐹 : 𝑅 ⟶ ℕ0 ) → ( 𝑀 Ramsey 𝐹 ) ∈ ( ℕ0 ∪ { +∞ } ) )