Metamath Proof Explorer


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 0 R V F : R 0 M Ramsey F 0 +∞

Proof

Step Hyp Ref Expression
1 eqid a V , i 0 b 𝒫 a | b = i = a V , i 0 b 𝒫 a | b = i
2 eqid n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c = n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c
3 1 2 ramcl2lem M 0 R V F : R 0 M Ramsey F = if n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c = +∞ sup n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c <
4 iftrue n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c = if n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c = +∞ sup n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c < = +∞
5 3 4 sylan9eq M 0 R V F : R 0 n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c = M Ramsey F = +∞
6 ssun2 +∞ 0 +∞
7 pnfex +∞ V
8 7 snss +∞ 0 +∞ +∞ 0 +∞
9 6 8 mpbir +∞ 0 +∞
10 5 9 eqeltrdi M 0 R V F : R 0 n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c = M Ramsey F 0 +∞
11 ssun1 0 0 +∞
12 1 2 ramtcl2 M 0 R V F : R 0 M Ramsey F 0 n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c
13 12 biimpar M 0 R V F : R 0 n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c M Ramsey F 0
14 11 13 sselid M 0 R V F : R 0 n 0 | s n s f R s a V , i 0 b 𝒫 a | b = i M c R x 𝒫 s F c x x a V , i 0 b 𝒫 a | b = i M f -1 c M Ramsey F 0 +∞
15 10 14 pm2.61dane M 0 R V F : R 0 M Ramsey F 0 +∞