| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-so | ⊢ ( 𝑅  Or  𝐴  ↔  ( 𝑅  Po  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) ) | 
						
							| 2 |  | opelxp | ⊢ ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐴  ×  𝐴 )  ↔  ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐴 ) ) | 
						
							| 3 |  | brun | ⊢ ( 𝑥 (  I   ∪  ◡ 𝑅 ) 𝑦  ↔  ( 𝑥  I  𝑦  ∨  𝑥 ◡ 𝑅 𝑦 ) ) | 
						
							| 4 |  | vex | ⊢ 𝑦  ∈  V | 
						
							| 5 | 4 | ideq | ⊢ ( 𝑥  I  𝑦  ↔  𝑥  =  𝑦 ) | 
						
							| 6 |  | vex | ⊢ 𝑥  ∈  V | 
						
							| 7 | 6 4 | brcnv | ⊢ ( 𝑥 ◡ 𝑅 𝑦  ↔  𝑦 𝑅 𝑥 ) | 
						
							| 8 | 5 7 | orbi12i | ⊢ ( ( 𝑥  I  𝑦  ∨  𝑥 ◡ 𝑅 𝑦 )  ↔  ( 𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) | 
						
							| 9 | 3 8 | bitr2i | ⊢ ( ( 𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 )  ↔  𝑥 (  I   ∪  ◡ 𝑅 ) 𝑦 ) | 
						
							| 10 | 9 | orbi2i | ⊢ ( ( 𝑥 𝑅 𝑦  ∨  ( 𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) )  ↔  ( 𝑥 𝑅 𝑦  ∨  𝑥 (  I   ∪  ◡ 𝑅 ) 𝑦 ) ) | 
						
							| 11 |  | 3orass | ⊢ ( ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 )  ↔  ( 𝑥 𝑅 𝑦  ∨  ( 𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) ) | 
						
							| 12 |  | brun | ⊢ ( 𝑥 ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) 𝑦  ↔  ( 𝑥 𝑅 𝑦  ∨  𝑥 (  I   ∪  ◡ 𝑅 ) 𝑦 ) ) | 
						
							| 13 | 10 11 12 | 3bitr4i | ⊢ ( ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 )  ↔  𝑥 ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) 𝑦 ) | 
						
							| 14 |  | df-br | ⊢ ( 𝑥 ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) 𝑦  ↔  〈 𝑥 ,  𝑦 〉  ∈  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) ) | 
						
							| 15 | 13 14 | bitr2i | ⊢ ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) )  ↔  ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) | 
						
							| 16 | 2 15 | imbi12i | ⊢ ( ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐴  ×  𝐴 )  →  〈 𝑥 ,  𝑦 〉  ∈  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) )  ↔  ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐴 )  →  ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) ) | 
						
							| 17 | 16 | 2albii | ⊢ ( ∀ 𝑥 ∀ 𝑦 ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐴  ×  𝐴 )  →  〈 𝑥 ,  𝑦 〉  ∈  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) )  ↔  ∀ 𝑥 ∀ 𝑦 ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐴 )  →  ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) ) | 
						
							| 18 |  | relxp | ⊢ Rel  ( 𝐴  ×  𝐴 ) | 
						
							| 19 |  | ssrel | ⊢ ( Rel  ( 𝐴  ×  𝐴 )  →  ( ( 𝐴  ×  𝐴 )  ⊆  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) )  ↔  ∀ 𝑥 ∀ 𝑦 ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐴  ×  𝐴 )  →  〈 𝑥 ,  𝑦 〉  ∈  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) ) ) ) | 
						
							| 20 | 18 19 | ax-mp | ⊢ ( ( 𝐴  ×  𝐴 )  ⊆  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) )  ↔  ∀ 𝑥 ∀ 𝑦 ( 〈 𝑥 ,  𝑦 〉  ∈  ( 𝐴  ×  𝐴 )  →  〈 𝑥 ,  𝑦 〉  ∈  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) ) ) | 
						
							| 21 |  | r2al | ⊢ ( ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 )  ↔  ∀ 𝑥 ∀ 𝑦 ( ( 𝑥  ∈  𝐴  ∧  𝑦  ∈  𝐴 )  →  ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) ) | 
						
							| 22 | 17 20 21 | 3bitr4i | ⊢ ( ( 𝐴  ×  𝐴 )  ⊆  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) )  ↔  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) | 
						
							| 23 | 22 | anbi2i | ⊢ ( ( 𝑅  Po  𝐴  ∧  ( 𝐴  ×  𝐴 )  ⊆  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) )  ↔  ( 𝑅  Po  𝐴  ∧  ∀ 𝑥  ∈  𝐴 ∀ 𝑦  ∈  𝐴 ( 𝑥 𝑅 𝑦  ∨  𝑥  =  𝑦  ∨  𝑦 𝑅 𝑥 ) ) ) | 
						
							| 24 | 1 23 | bitr4i | ⊢ ( 𝑅  Or  𝐴  ↔  ( 𝑅  Po  𝐴  ∧  ( 𝐴  ×  𝐴 )  ⊆  ( 𝑅  ∪  (  I   ∪  ◡ 𝑅 ) ) ) ) |