| Step | Hyp | Ref | Expression | 
						
							| 1 |  | addsproplem.1 | ⊢ ( 𝜑  →  ∀ 𝑥  ∈   No  ∀ 𝑦  ∈   No  ∀ 𝑧  ∈   No  ( ( ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑦 ) )  ∪  ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑧 ) ) )  ∈  ( ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑌 ) )  ∪  ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑍 ) ) )  →  ( ( 𝑥  +s  𝑦 )  ∈   No   ∧  ( 𝑦  <s  𝑧  →  ( 𝑦  +s  𝑥 )  <s  ( 𝑧  +s  𝑥 ) ) ) ) ) | 
						
							| 2 |  | addspropord.2 | ⊢ ( 𝜑  →  𝑋  ∈   No  ) | 
						
							| 3 |  | addspropord.3 | ⊢ ( 𝜑  →  𝑌  ∈   No  ) | 
						
							| 4 |  | addspropord.4 | ⊢ ( 𝜑  →  𝑍  ∈   No  ) | 
						
							| 5 |  | addspropord.5 | ⊢ ( 𝜑  →  𝑌  <s  𝑍 ) | 
						
							| 6 |  | bdayelon | ⊢ (  bday  ‘ 𝑌 )  ∈  On | 
						
							| 7 |  | fvex | ⊢ (  bday  ‘ 𝑌 )  ∈  V | 
						
							| 8 | 7 | elon | ⊢ ( (  bday  ‘ 𝑌 )  ∈  On  ↔  Ord  (  bday  ‘ 𝑌 ) ) | 
						
							| 9 | 6 8 | mpbi | ⊢ Ord  (  bday  ‘ 𝑌 ) | 
						
							| 10 |  | bdayelon | ⊢ (  bday  ‘ 𝑍 )  ∈  On | 
						
							| 11 |  | fvex | ⊢ (  bday  ‘ 𝑍 )  ∈  V | 
						
							| 12 | 11 | elon | ⊢ ( (  bday  ‘ 𝑍 )  ∈  On  ↔  Ord  (  bday  ‘ 𝑍 ) ) | 
						
							| 13 | 10 12 | mpbi | ⊢ Ord  (  bday  ‘ 𝑍 ) | 
						
							| 14 |  | ordtri3or | ⊢ ( ( Ord  (  bday  ‘ 𝑌 )  ∧  Ord  (  bday  ‘ 𝑍 ) )  →  ( (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 )  ∨  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 )  ∨  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) ) ) | 
						
							| 15 | 9 13 14 | mp2an | ⊢ ( (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 )  ∨  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 )  ∨  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) ) | 
						
							| 16 |  | simpl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  𝜑 ) | 
						
							| 17 | 16 1 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  ∀ 𝑥  ∈   No  ∀ 𝑦  ∈   No  ∀ 𝑧  ∈   No  ( ( ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑦 ) )  ∪  ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑧 ) ) )  ∈  ( ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑌 ) )  ∪  ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑍 ) ) )  →  ( ( 𝑥  +s  𝑦 )  ∈   No   ∧  ( 𝑦  <s  𝑧  →  ( 𝑦  +s  𝑥 )  <s  ( 𝑧  +s  𝑥 ) ) ) ) ) | 
						
							| 18 | 16 2 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  𝑋  ∈   No  ) | 
						
							| 19 | 16 3 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  𝑌  ∈   No  ) | 
						
							| 20 | 16 4 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  𝑍  ∈   No  ) | 
						
							| 21 | 16 5 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  𝑌  <s  𝑍 ) | 
						
							| 22 |  | simpr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) ) | 
						
							| 23 | 17 18 19 20 21 22 | addsproplem4 | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 ) )  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) | 
						
							| 24 | 23 | ex | ⊢ ( 𝜑  →  ( (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 )  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) ) | 
						
							| 25 |  | simpl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  𝜑 ) | 
						
							| 26 | 25 1 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  ∀ 𝑥  ∈   No  ∀ 𝑦  ∈   No  ∀ 𝑧  ∈   No  ( ( ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑦 ) )  ∪  ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑧 ) ) )  ∈  ( ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑌 ) )  ∪  ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑍 ) ) )  →  ( ( 𝑥  +s  𝑦 )  ∈   No   ∧  ( 𝑦  <s  𝑧  →  ( 𝑦  +s  𝑥 )  <s  ( 𝑧  +s  𝑥 ) ) ) ) ) | 
						
							| 27 | 25 2 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  𝑋  ∈   No  ) | 
						
							| 28 | 25 3 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  𝑌  ∈   No  ) | 
						
							| 29 | 25 4 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  𝑍  ∈   No  ) | 
						
							| 30 | 25 5 | syl | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  𝑌  <s  𝑍 ) | 
						
							| 31 |  | simpr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) ) | 
						
							| 32 | 26 27 28 29 30 31 | addsproplem6 | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 ) )  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) | 
						
							| 33 | 32 | ex | ⊢ ( 𝜑  →  ( (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 )  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) ) | 
						
							| 34 | 1 | adantr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  ∀ 𝑥  ∈   No  ∀ 𝑦  ∈   No  ∀ 𝑧  ∈   No  ( ( ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑦 ) )  ∪  ( (  bday  ‘ 𝑥 )  +no  (  bday  ‘ 𝑧 ) ) )  ∈  ( ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑌 ) )  ∪  ( (  bday  ‘ 𝑋 )  +no  (  bday  ‘ 𝑍 ) ) )  →  ( ( 𝑥  +s  𝑦 )  ∈   No   ∧  ( 𝑦  <s  𝑧  →  ( 𝑦  +s  𝑥 )  <s  ( 𝑧  +s  𝑥 ) ) ) ) ) | 
						
							| 35 | 2 | adantr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  𝑋  ∈   No  ) | 
						
							| 36 | 3 | adantr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  𝑌  ∈   No  ) | 
						
							| 37 | 4 | adantr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  𝑍  ∈   No  ) | 
						
							| 38 | 5 | adantr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  𝑌  <s  𝑍 ) | 
						
							| 39 |  | simpr | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) ) | 
						
							| 40 | 34 35 36 37 38 39 | addsproplem5 | ⊢ ( ( 𝜑  ∧  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) | 
						
							| 41 | 40 | ex | ⊢ ( 𝜑  →  ( (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 )  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) ) | 
						
							| 42 | 24 33 41 | 3jaod | ⊢ ( 𝜑  →  ( ( (  bday  ‘ 𝑌 )  ∈  (  bday  ‘ 𝑍 )  ∨  (  bday  ‘ 𝑌 )  =  (  bday  ‘ 𝑍 )  ∨  (  bday  ‘ 𝑍 )  ∈  (  bday  ‘ 𝑌 ) )  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) ) | 
						
							| 43 | 15 42 | mpi | ⊢ ( 𝜑  →  ( 𝑌  +s  𝑋 )  <s  ( 𝑍  +s  𝑋 ) ) |