| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							1sdom2 | 
							⊢ 1o  ≺  2o  | 
						
						
							| 2 | 
							
								
							 | 
							djuxpdom | 
							⊢ ( ( 1o  ≺  𝐴  ∧  1o  ≺  2o )  →  ( 𝐴  ⊔  2o )  ≼  ( 𝐴  ×  2o ) )  | 
						
						
							| 3 | 
							
								1 2
							 | 
							mpan2 | 
							⊢ ( 1o  ≺  𝐴  →  ( 𝐴  ⊔  2o )  ≼  ( 𝐴  ×  2o ) )  | 
						
						
							| 4 | 
							
								
							 | 
							sdom0 | 
							⊢ ¬  1o  ≺  ∅  | 
						
						
							| 5 | 
							
								
							 | 
							breq2 | 
							⊢ ( 𝐴  =  ∅  →  ( 1o  ≺  𝐴  ↔  1o  ≺  ∅ ) )  | 
						
						
							| 6 | 
							
								4 5
							 | 
							mtbiri | 
							⊢ ( 𝐴  =  ∅  →  ¬  1o  ≺  𝐴 )  | 
						
						
							| 7 | 
							
								6
							 | 
							con2i | 
							⊢ ( 1o  ≺  𝐴  →  ¬  𝐴  =  ∅ )  | 
						
						
							| 8 | 
							
								
							 | 
							neq0 | 
							⊢ ( ¬  𝐴  =  ∅  ↔  ∃ 𝑥 𝑥  ∈  𝐴 )  | 
						
						
							| 9 | 
							
								7 8
							 | 
							sylib | 
							⊢ ( 1o  ≺  𝐴  →  ∃ 𝑥 𝑥  ∈  𝐴 )  | 
						
						
							| 10 | 
							
								
							 | 
							relsdom | 
							⊢ Rel   ≺   | 
						
						
							| 11 | 
							
								10
							 | 
							brrelex2i | 
							⊢ ( 1o  ≺  𝐴  →  𝐴  ∈  V )  | 
						
						
							| 12 | 
							
								11
							 | 
							adantr | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  𝐴  ∈  V )  | 
						
						
							| 13 | 
							
								
							 | 
							enrefg | 
							⊢ ( 𝐴  ∈  V  →  𝐴  ≈  𝐴 )  | 
						
						
							| 14 | 
							
								12 13
							 | 
							syl | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  𝐴  ≈  𝐴 )  | 
						
						
							| 15 | 
							
								
							 | 
							df2o2 | 
							⊢ 2o  =  { ∅ ,  { ∅ } }  | 
						
						
							| 16 | 
							
								
							 | 
							pwpw0 | 
							⊢ 𝒫  { ∅ }  =  { ∅ ,  { ∅ } }  | 
						
						
							| 17 | 
							
								15 16
							 | 
							eqtr4i | 
							⊢ 2o  =  𝒫  { ∅ }  | 
						
						
							| 18 | 
							
								
							 | 
							0ex | 
							⊢ ∅  ∈  V  | 
						
						
							| 19 | 
							
								
							 | 
							vex | 
							⊢ 𝑥  ∈  V  | 
						
						
							| 20 | 
							
								
							 | 
							en2sn | 
							⊢ ( ( ∅  ∈  V  ∧  𝑥  ∈  V )  →  { ∅ }  ≈  { 𝑥 } )  | 
						
						
							| 21 | 
							
								18 19 20
							 | 
							mp2an | 
							⊢ { ∅ }  ≈  { 𝑥 }  | 
						
						
							| 22 | 
							
								
							 | 
							pwen | 
							⊢ ( { ∅ }  ≈  { 𝑥 }  →  𝒫  { ∅ }  ≈  𝒫  { 𝑥 } )  | 
						
						
							| 23 | 
							
								21 22
							 | 
							ax-mp | 
							⊢ 𝒫  { ∅ }  ≈  𝒫  { 𝑥 }  | 
						
						
							| 24 | 
							
								17 23
							 | 
							eqbrtri | 
							⊢ 2o  ≈  𝒫  { 𝑥 }  | 
						
						
							| 25 | 
							
								
							 | 
							xpen | 
							⊢ ( ( 𝐴  ≈  𝐴  ∧  2o  ≈  𝒫  { 𝑥 } )  →  ( 𝐴  ×  2o )  ≈  ( 𝐴  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 26 | 
							
								14 24 25
							 | 
							sylancl | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( 𝐴  ×  2o )  ≈  ( 𝐴  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 27 | 
							
								
							 | 
							vsnex | 
							⊢ { 𝑥 }  ∈  V  | 
						
						
							| 28 | 
							
								27
							 | 
							pwex | 
							⊢ 𝒫  { 𝑥 }  ∈  V  | 
						
						
							| 29 | 
							
								
							 | 
							uncom | 
							⊢ ( ( 𝐴  ∖  { 𝑥 } )  ∪  { 𝑥 } )  =  ( { 𝑥 }  ∪  ( 𝐴  ∖  { 𝑥 } ) )  | 
						
						
							| 30 | 
							
								
							 | 
							simpr | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  𝑥  ∈  𝐴 )  | 
						
						
							| 31 | 
							
								30
							 | 
							snssd | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  { 𝑥 }  ⊆  𝐴 )  | 
						
						
							| 32 | 
							
								
							 | 
							undif | 
							⊢ ( { 𝑥 }  ⊆  𝐴  ↔  ( { 𝑥 }  ∪  ( 𝐴  ∖  { 𝑥 } ) )  =  𝐴 )  | 
						
						
							| 33 | 
							
								31 32
							 | 
							sylib | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( { 𝑥 }  ∪  ( 𝐴  ∖  { 𝑥 } ) )  =  𝐴 )  | 
						
						
							| 34 | 
							
								29 33
							 | 
							eqtrid | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( ( 𝐴  ∖  { 𝑥 } )  ∪  { 𝑥 } )  =  𝐴 )  | 
						
						
							| 35 | 
							
								12
							 | 
							difexd | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( 𝐴  ∖  { 𝑥 } )  ∈  V )  | 
						
						
							| 36 | 
							
								
							 | 
							canth2g | 
							⊢ ( ( 𝐴  ∖  { 𝑥 } )  ∈  V  →  ( 𝐴  ∖  { 𝑥 } )  ≺  𝒫  ( 𝐴  ∖  { 𝑥 } ) )  | 
						
						
							| 37 | 
							
								
							 | 
							domunsn | 
							⊢ ( ( 𝐴  ∖  { 𝑥 } )  ≺  𝒫  ( 𝐴  ∖  { 𝑥 } )  →  ( ( 𝐴  ∖  { 𝑥 } )  ∪  { 𝑥 } )  ≼  𝒫  ( 𝐴  ∖  { 𝑥 } ) )  | 
						
						
							| 38 | 
							
								35 36 37
							 | 
							3syl | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( ( 𝐴  ∖  { 𝑥 } )  ∪  { 𝑥 } )  ≼  𝒫  ( 𝐴  ∖  { 𝑥 } ) )  | 
						
						
							| 39 | 
							
								34 38
							 | 
							eqbrtrrd | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  𝐴  ≼  𝒫  ( 𝐴  ∖  { 𝑥 } ) )  | 
						
						
							| 40 | 
							
								
							 | 
							xpdom1g | 
							⊢ ( ( 𝒫  { 𝑥 }  ∈  V  ∧  𝐴  ≼  𝒫  ( 𝐴  ∖  { 𝑥 } ) )  →  ( 𝐴  ×  𝒫  { 𝑥 } )  ≼  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 41 | 
							
								28 39 40
							 | 
							sylancr | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( 𝐴  ×  𝒫  { 𝑥 } )  ≼  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 42 | 
							
								
							 | 
							endomtr | 
							⊢ ( ( ( 𝐴  ×  2o )  ≈  ( 𝐴  ×  𝒫  { 𝑥 } )  ∧  ( 𝐴  ×  𝒫  { 𝑥 } )  ≼  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } ) )  →  ( 𝐴  ×  2o )  ≼  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 43 | 
							
								26 41 42
							 | 
							syl2anc | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( 𝐴  ×  2o )  ≼  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 44 | 
							
								
							 | 
							pwdjuen | 
							⊢ ( ( ( 𝐴  ∖  { 𝑥 } )  ∈  V  ∧  { 𝑥 }  ∈  V )  →  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 45 | 
							
								35 27 44
							 | 
							sylancl | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } ) )  | 
						
						
							| 46 | 
							
								45
							 | 
							ensymd | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } )  ≈  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } ) )  | 
						
						
							| 47 | 
							
								
							 | 
							domentr | 
							⊢ ( ( ( 𝐴  ×  2o )  ≼  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } )  ∧  ( 𝒫  ( 𝐴  ∖  { 𝑥 } )  ×  𝒫  { 𝑥 } )  ≈  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } ) )  →  ( 𝐴  ×  2o )  ≼  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } ) )  | 
						
						
							| 48 | 
							
								43 46 47
							 | 
							syl2anc | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( 𝐴  ×  2o )  ≼  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } ) )  | 
						
						
							| 49 | 
							
								27
							 | 
							a1i | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  { 𝑥 }  ∈  V )  | 
						
						
							| 50 | 
							
								
							 | 
							disjdifr | 
							⊢ ( ( 𝐴  ∖  { 𝑥 } )  ∩  { 𝑥 } )  =  ∅  | 
						
						
							| 51 | 
							
								50
							 | 
							a1i | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( ( 𝐴  ∖  { 𝑥 } )  ∩  { 𝑥 } )  =  ∅ )  | 
						
						
							| 52 | 
							
								
							 | 
							endjudisj | 
							⊢ ( ( ( 𝐴  ∖  { 𝑥 } )  ∈  V  ∧  { 𝑥 }  ∈  V  ∧  ( ( 𝐴  ∖  { 𝑥 } )  ∩  { 𝑥 } )  =  ∅ )  →  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  ( ( 𝐴  ∖  { 𝑥 } )  ∪  { 𝑥 } ) )  | 
						
						
							| 53 | 
							
								35 49 51 52
							 | 
							syl3anc | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  ( ( 𝐴  ∖  { 𝑥 } )  ∪  { 𝑥 } ) )  | 
						
						
							| 54 | 
							
								53 34
							 | 
							breqtrd | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  𝐴 )  | 
						
						
							| 55 | 
							
								
							 | 
							pwen | 
							⊢ ( ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  𝐴  →  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  𝒫  𝐴 )  | 
						
						
							| 56 | 
							
								54 55
							 | 
							syl | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  𝒫  𝐴 )  | 
						
						
							| 57 | 
							
								
							 | 
							domentr | 
							⊢ ( ( ( 𝐴  ×  2o )  ≼  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ∧  𝒫  ( ( 𝐴  ∖  { 𝑥 } )  ⊔  { 𝑥 } )  ≈  𝒫  𝐴 )  →  ( 𝐴  ×  2o )  ≼  𝒫  𝐴 )  | 
						
						
							| 58 | 
							
								48 56 57
							 | 
							syl2anc | 
							⊢ ( ( 1o  ≺  𝐴  ∧  𝑥  ∈  𝐴 )  →  ( 𝐴  ×  2o )  ≼  𝒫  𝐴 )  | 
						
						
							| 59 | 
							
								9 58
							 | 
							exlimddv | 
							⊢ ( 1o  ≺  𝐴  →  ( 𝐴  ×  2o )  ≼  𝒫  𝐴 )  | 
						
						
							| 60 | 
							
								
							 | 
							domtr | 
							⊢ ( ( ( 𝐴  ⊔  2o )  ≼  ( 𝐴  ×  2o )  ∧  ( 𝐴  ×  2o )  ≼  𝒫  𝐴 )  →  ( 𝐴  ⊔  2o )  ≼  𝒫  𝐴 )  | 
						
						
							| 61 | 
							
								3 59 60
							 | 
							syl2anc | 
							⊢ ( 1o  ≺  𝐴  →  ( 𝐴  ⊔  2o )  ≼  𝒫  𝐴 )  |