| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ovexd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∈  V ) | 
						
							| 2 |  | ovexd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝐶  ↑m  𝐴 )  ∈  V ) | 
						
							| 3 |  | ovexd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝐶  ↑m  𝐵 )  ∈  V ) | 
						
							| 4 | 2 3 | xpexd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  ∈  V ) | 
						
							| 5 |  | elmapi | ⊢ ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  →  𝑥 : ( 𝐴  ∪  𝐵 ) ⟶ 𝐶 ) | 
						
							| 6 |  | ssun1 | ⊢ 𝐴  ⊆  ( 𝐴  ∪  𝐵 ) | 
						
							| 7 |  | fssres | ⊢ ( ( 𝑥 : ( 𝐴  ∪  𝐵 ) ⟶ 𝐶  ∧  𝐴  ⊆  ( 𝐴  ∪  𝐵 ) )  →  ( 𝑥  ↾  𝐴 ) : 𝐴 ⟶ 𝐶 ) | 
						
							| 8 | 5 6 7 | sylancl | ⊢ ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  →  ( 𝑥  ↾  𝐴 ) : 𝐴 ⟶ 𝐶 ) | 
						
							| 9 |  | ssun2 | ⊢ 𝐵  ⊆  ( 𝐴  ∪  𝐵 ) | 
						
							| 10 |  | fssres | ⊢ ( ( 𝑥 : ( 𝐴  ∪  𝐵 ) ⟶ 𝐶  ∧  𝐵  ⊆  ( 𝐴  ∪  𝐵 ) )  →  ( 𝑥  ↾  𝐵 ) : 𝐵 ⟶ 𝐶 ) | 
						
							| 11 | 5 9 10 | sylancl | ⊢ ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  →  ( 𝑥  ↾  𝐵 ) : 𝐵 ⟶ 𝐶 ) | 
						
							| 12 | 8 11 | jca | ⊢ ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  →  ( ( 𝑥  ↾  𝐴 ) : 𝐴 ⟶ 𝐶  ∧  ( 𝑥  ↾  𝐵 ) : 𝐵 ⟶ 𝐶 ) ) | 
						
							| 13 |  | opelxp | ⊢ ( 〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  ↔  ( ( 𝑥  ↾  𝐴 )  ∈  ( 𝐶  ↑m  𝐴 )  ∧  ( 𝑥  ↾  𝐵 )  ∈  ( 𝐶  ↑m  𝐵 ) ) ) | 
						
							| 14 |  | simpl3 | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  𝐶  ∈  𝑋 ) | 
						
							| 15 |  | simpl1 | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  𝐴  ∈  𝑉 ) | 
						
							| 16 | 14 15 | elmapd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( ( 𝑥  ↾  𝐴 )  ∈  ( 𝐶  ↑m  𝐴 )  ↔  ( 𝑥  ↾  𝐴 ) : 𝐴 ⟶ 𝐶 ) ) | 
						
							| 17 |  | simpl2 | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  𝐵  ∈  𝑊 ) | 
						
							| 18 | 14 17 | elmapd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( ( 𝑥  ↾  𝐵 )  ∈  ( 𝐶  ↑m  𝐵 )  ↔  ( 𝑥  ↾  𝐵 ) : 𝐵 ⟶ 𝐶 ) ) | 
						
							| 19 | 16 18 | anbi12d | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( ( ( 𝑥  ↾  𝐴 )  ∈  ( 𝐶  ↑m  𝐴 )  ∧  ( 𝑥  ↾  𝐵 )  ∈  ( 𝐶  ↑m  𝐵 ) )  ↔  ( ( 𝑥  ↾  𝐴 ) : 𝐴 ⟶ 𝐶  ∧  ( 𝑥  ↾  𝐵 ) : 𝐵 ⟶ 𝐶 ) ) ) | 
						
							| 20 | 13 19 | bitrid | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  ↔  ( ( 𝑥  ↾  𝐴 ) : 𝐴 ⟶ 𝐶  ∧  ( 𝑥  ↾  𝐵 ) : 𝐵 ⟶ 𝐶 ) ) ) | 
						
							| 21 | 12 20 | imbitrrid | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  →  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) ) | 
						
							| 22 |  | xp1st | ⊢ ( 𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  →  ( 1st  ‘ 𝑦 )  ∈  ( 𝐶  ↑m  𝐴 ) ) | 
						
							| 23 | 22 | adantl | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) )  →  ( 1st  ‘ 𝑦 )  ∈  ( 𝐶  ↑m  𝐴 ) ) | 
						
							| 24 |  | elmapi | ⊢ ( ( 1st  ‘ 𝑦 )  ∈  ( 𝐶  ↑m  𝐴 )  →  ( 1st  ‘ 𝑦 ) : 𝐴 ⟶ 𝐶 ) | 
						
							| 25 | 23 24 | syl | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) )  →  ( 1st  ‘ 𝑦 ) : 𝐴 ⟶ 𝐶 ) | 
						
							| 26 |  | xp2nd | ⊢ ( 𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  →  ( 2nd  ‘ 𝑦 )  ∈  ( 𝐶  ↑m  𝐵 ) ) | 
						
							| 27 | 26 | adantl | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) )  →  ( 2nd  ‘ 𝑦 )  ∈  ( 𝐶  ↑m  𝐵 ) ) | 
						
							| 28 |  | elmapi | ⊢ ( ( 2nd  ‘ 𝑦 )  ∈  ( 𝐶  ↑m  𝐵 )  →  ( 2nd  ‘ 𝑦 ) : 𝐵 ⟶ 𝐶 ) | 
						
							| 29 | 27 28 | syl | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) )  →  ( 2nd  ‘ 𝑦 ) : 𝐵 ⟶ 𝐶 ) | 
						
							| 30 |  | simplr | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) )  →  ( 𝐴  ∩  𝐵 )  =  ∅ ) | 
						
							| 31 | 25 29 30 | fun2d | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) )  →  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) ) : ( 𝐴  ∪  𝐵 ) ⟶ 𝐶 ) | 
						
							| 32 | 31 | ex | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  →  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) ) : ( 𝐴  ∪  𝐵 ) ⟶ 𝐶 ) ) | 
						
							| 33 |  | unexg | ⊢ ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊 )  →  ( 𝐴  ∪  𝐵 )  ∈  V ) | 
						
							| 34 | 15 17 33 | syl2anc | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝐴  ∪  𝐵 )  ∈  V ) | 
						
							| 35 | 14 34 | elmapd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ↔  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) ) : ( 𝐴  ∪  𝐵 ) ⟶ 𝐶 ) ) | 
						
							| 36 | 32 35 | sylibrd | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  →  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) ) ) ) | 
						
							| 37 |  | 1st2nd2 | ⊢ ( 𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) )  →  𝑦  =  〈 ( 1st  ‘ 𝑦 ) ,  ( 2nd  ‘ 𝑦 ) 〉 ) | 
						
							| 38 | 37 | ad2antll | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  𝑦  =  〈 ( 1st  ‘ 𝑦 ) ,  ( 2nd  ‘ 𝑦 ) 〉 ) | 
						
							| 39 | 25 | adantrl | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( 1st  ‘ 𝑦 ) : 𝐴 ⟶ 𝐶 ) | 
						
							| 40 | 29 | adantrl | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( 2nd  ‘ 𝑦 ) : 𝐵 ⟶ 𝐶 ) | 
						
							| 41 |  | res0 | ⊢ ( ( 1st  ‘ 𝑦 )  ↾  ∅ )  =  ∅ | 
						
							| 42 |  | res0 | ⊢ ( ( 2nd  ‘ 𝑦 )  ↾  ∅ )  =  ∅ | 
						
							| 43 | 41 42 | eqtr4i | ⊢ ( ( 1st  ‘ 𝑦 )  ↾  ∅ )  =  ( ( 2nd  ‘ 𝑦 )  ↾  ∅ ) | 
						
							| 44 |  | simplr | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( 𝐴  ∩  𝐵 )  =  ∅ ) | 
						
							| 45 | 44 | reseq2d | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( ( 1st  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) )  =  ( ( 1st  ‘ 𝑦 )  ↾  ∅ ) ) | 
						
							| 46 | 44 | reseq2d | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( ( 2nd  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) )  =  ( ( 2nd  ‘ 𝑦 )  ↾  ∅ ) ) | 
						
							| 47 | 43 45 46 | 3eqtr4a | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( ( 1st  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) )  =  ( ( 2nd  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) ) ) | 
						
							| 48 |  | fresaunres1 | ⊢ ( ( ( 1st  ‘ 𝑦 ) : 𝐴 ⟶ 𝐶  ∧  ( 2nd  ‘ 𝑦 ) : 𝐵 ⟶ 𝐶  ∧  ( ( 1st  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) )  =  ( ( 2nd  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) ) )  →  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐴 )  =  ( 1st  ‘ 𝑦 ) ) | 
						
							| 49 | 39 40 47 48 | syl3anc | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐴 )  =  ( 1st  ‘ 𝑦 ) ) | 
						
							| 50 |  | fresaunres2 | ⊢ ( ( ( 1st  ‘ 𝑦 ) : 𝐴 ⟶ 𝐶  ∧  ( 2nd  ‘ 𝑦 ) : 𝐵 ⟶ 𝐶  ∧  ( ( 1st  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) )  =  ( ( 2nd  ‘ 𝑦 )  ↾  ( 𝐴  ∩  𝐵 ) ) )  →  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐵 )  =  ( 2nd  ‘ 𝑦 ) ) | 
						
							| 51 | 39 40 47 50 | syl3anc | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐵 )  =  ( 2nd  ‘ 𝑦 ) ) | 
						
							| 52 | 49 51 | opeq12d | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  〈 ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐴 ) ,  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐵 ) 〉  =  〈 ( 1st  ‘ 𝑦 ) ,  ( 2nd  ‘ 𝑦 ) 〉 ) | 
						
							| 53 | 38 52 | eqtr4d | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  𝑦  =  〈 ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐴 ) ,  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐵 ) 〉 ) | 
						
							| 54 |  | reseq1 | ⊢ ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  →  ( 𝑥  ↾  𝐴 )  =  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐴 ) ) | 
						
							| 55 |  | reseq1 | ⊢ ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  →  ( 𝑥  ↾  𝐵 )  =  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐵 ) ) | 
						
							| 56 | 54 55 | opeq12d | ⊢ ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  →  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  =  〈 ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐴 ) ,  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐵 ) 〉 ) | 
						
							| 57 | 56 | eqeq2d | ⊢ ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  →  ( 𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  ↔  𝑦  =  〈 ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐴 ) ,  ( ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↾  𝐵 ) 〉 ) ) | 
						
							| 58 | 53 57 | syl5ibrcom | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  →  𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉 ) ) | 
						
							| 59 |  | ffn | ⊢ ( 𝑥 : ( 𝐴  ∪  𝐵 ) ⟶ 𝐶  →  𝑥  Fn  ( 𝐴  ∪  𝐵 ) ) | 
						
							| 60 |  | fnresdm | ⊢ ( 𝑥  Fn  ( 𝐴  ∪  𝐵 )  →  ( 𝑥  ↾  ( 𝐴  ∪  𝐵 ) )  =  𝑥 ) | 
						
							| 61 | 5 59 60 | 3syl | ⊢ ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  →  ( 𝑥  ↾  ( 𝐴  ∪  𝐵 ) )  =  𝑥 ) | 
						
							| 62 | 61 | ad2antrl | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( 𝑥  ↾  ( 𝐴  ∪  𝐵 ) )  =  𝑥 ) | 
						
							| 63 | 62 | eqcomd | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  𝑥  =  ( 𝑥  ↾  ( 𝐴  ∪  𝐵 ) ) ) | 
						
							| 64 |  | vex | ⊢ 𝑥  ∈  V | 
						
							| 65 | 64 | resex | ⊢ ( 𝑥  ↾  𝐴 )  ∈  V | 
						
							| 66 | 64 | resex | ⊢ ( 𝑥  ↾  𝐵 )  ∈  V | 
						
							| 67 | 65 66 | op1std | ⊢ ( 𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  →  ( 1st  ‘ 𝑦 )  =  ( 𝑥  ↾  𝐴 ) ) | 
						
							| 68 | 65 66 | op2ndd | ⊢ ( 𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  →  ( 2nd  ‘ 𝑦 )  =  ( 𝑥  ↾  𝐵 ) ) | 
						
							| 69 | 67 68 | uneq12d | ⊢ ( 𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  →  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  =  ( ( 𝑥  ↾  𝐴 )  ∪  ( 𝑥  ↾  𝐵 ) ) ) | 
						
							| 70 |  | resundi | ⊢ ( 𝑥  ↾  ( 𝐴  ∪  𝐵 ) )  =  ( ( 𝑥  ↾  𝐴 )  ∪  ( 𝑥  ↾  𝐵 ) ) | 
						
							| 71 | 69 70 | eqtr4di | ⊢ ( 𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  →  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  =  ( 𝑥  ↾  ( 𝐴  ∪  𝐵 ) ) ) | 
						
							| 72 | 71 | eqeq2d | ⊢ ( 𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  →  ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↔  𝑥  =  ( 𝑥  ↾  ( 𝐴  ∪  𝐵 ) ) ) ) | 
						
							| 73 | 63 72 | syl5ibrcom | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( 𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉  →  𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) ) ) ) | 
						
							| 74 | 58 73 | impbid | ⊢ ( ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  ∧  ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) )  →  ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↔  𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉 ) ) | 
						
							| 75 | 74 | ex | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( ( 𝑥  ∈  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ∧  𝑦  ∈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) )  →  ( 𝑥  =  ( ( 1st  ‘ 𝑦 )  ∪  ( 2nd  ‘ 𝑦 ) )  ↔  𝑦  =  〈 ( 𝑥  ↾  𝐴 ) ,  ( 𝑥  ↾  𝐵 ) 〉 ) ) ) | 
						
							| 76 | 1 4 21 36 75 | en3d | ⊢ ( ( ( 𝐴  ∈  𝑉  ∧  𝐵  ∈  𝑊  ∧  𝐶  ∈  𝑋 )  ∧  ( 𝐴  ∩  𝐵 )  =  ∅ )  →  ( 𝐶  ↑m  ( 𝐴  ∪  𝐵 ) )  ≈  ( ( 𝐶  ↑m  𝐴 )  ×  ( 𝐶  ↑m  𝐵 ) ) ) |