| Step | Hyp | Ref | Expression | 
						
							| 1 |  | prproropf1o.o | ⊢ 𝑂  =  ( 𝑅  ∩  ( 𝑉  ×  𝑉 ) ) | 
						
							| 2 |  | prproropf1o.p | ⊢ 𝑃  =  { 𝑝  ∈  𝒫  𝑉  ∣  ( ♯ ‘ 𝑝 )  =  2 } | 
						
							| 3 | 1 | prproropf1olem0 | ⊢ ( 𝑊  ∈  𝑂  ↔  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) ) | 
						
							| 4 |  | simpr2 | ⊢ ( ( 𝑅  Or  𝑉  ∧  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) )  →  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 ) ) | 
						
							| 5 |  | prelpwi | ⊢ ( ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  →  { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  ∈  𝒫  𝑉 ) | 
						
							| 6 | 4 5 | syl | ⊢ ( ( 𝑅  Or  𝑉  ∧  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) )  →  { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  ∈  𝒫  𝑉 ) | 
						
							| 7 |  | sopo | ⊢ ( 𝑅  Or  𝑉  →  𝑅  Po  𝑉 ) | 
						
							| 8 | 7 | adantr | ⊢ ( ( 𝑅  Or  𝑉  ∧  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) )  →  𝑅  Po  𝑉 ) | 
						
							| 9 |  | simpr3 | ⊢ ( ( 𝑅  Or  𝑉  ∧  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) )  →  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) | 
						
							| 10 |  | po2ne | ⊢ ( ( 𝑅  Po  𝑉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) )  →  ( 1st  ‘ 𝑊 )  ≠  ( 2nd  ‘ 𝑊 ) ) | 
						
							| 11 | 8 4 9 10 | syl3anc | ⊢ ( ( 𝑅  Or  𝑉  ∧  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) )  →  ( 1st  ‘ 𝑊 )  ≠  ( 2nd  ‘ 𝑊 ) ) | 
						
							| 12 |  | fvex | ⊢ ( 1st  ‘ 𝑊 )  ∈  V | 
						
							| 13 |  | fvex | ⊢ ( 2nd  ‘ 𝑊 )  ∈  V | 
						
							| 14 |  | hashprg | ⊢ ( ( ( 1st  ‘ 𝑊 )  ∈  V  ∧  ( 2nd  ‘ 𝑊 )  ∈  V )  →  ( ( 1st  ‘ 𝑊 )  ≠  ( 2nd  ‘ 𝑊 )  ↔  ( ♯ ‘ { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) } )  =  2 ) ) | 
						
							| 15 | 12 13 14 | mp2an | ⊢ ( ( 1st  ‘ 𝑊 )  ≠  ( 2nd  ‘ 𝑊 )  ↔  ( ♯ ‘ { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) } )  =  2 ) | 
						
							| 16 | 11 15 | sylib | ⊢ ( ( 𝑅  Or  𝑉  ∧  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) )  →  ( ♯ ‘ { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) } )  =  2 ) | 
						
							| 17 | 6 16 | jca | ⊢ ( ( 𝑅  Or  𝑉  ∧  ( 𝑊  =  〈 ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) 〉  ∧  ( ( 1st  ‘ 𝑊 )  ∈  𝑉  ∧  ( 2nd  ‘ 𝑊 )  ∈  𝑉 )  ∧  ( 1st  ‘ 𝑊 ) 𝑅 ( 2nd  ‘ 𝑊 ) ) )  →  ( { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  ∈  𝒫  𝑉  ∧  ( ♯ ‘ { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) } )  =  2 ) ) | 
						
							| 18 | 3 17 | sylan2b | ⊢ ( ( 𝑅  Or  𝑉  ∧  𝑊  ∈  𝑂 )  →  ( { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  ∈  𝒫  𝑉  ∧  ( ♯ ‘ { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) } )  =  2 ) ) | 
						
							| 19 |  | fveqeq2 | ⊢ ( 𝑝  =  { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  →  ( ( ♯ ‘ 𝑝 )  =  2  ↔  ( ♯ ‘ { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) } )  =  2 ) ) | 
						
							| 20 | 19 2 | elrab2 | ⊢ ( { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  ∈  𝑃  ↔  ( { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  ∈  𝒫  𝑉  ∧  ( ♯ ‘ { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) } )  =  2 ) ) | 
						
							| 21 | 18 20 | sylibr | ⊢ ( ( 𝑅  Or  𝑉  ∧  𝑊  ∈  𝑂 )  →  { ( 1st  ‘ 𝑊 ) ,  ( 2nd  ‘ 𝑊 ) }  ∈  𝑃 ) |