| Step | Hyp | Ref | Expression | 
						
							| 1 |  | pw2f1o2.f | ⊢ 𝐹  =  ( 𝑥  ∈  ( 2o  ↑m  𝐴 )  ↦  ( ◡ 𝑥  “  { 1o } ) ) | 
						
							| 2 |  | vex | ⊢ 𝑥  ∈  V | 
						
							| 3 | 2 | cnvex | ⊢ ◡ 𝑥  ∈  V | 
						
							| 4 |  | imaexg | ⊢ ( ◡ 𝑥  ∈  V  →  ( ◡ 𝑥  “  { 1o } )  ∈  V ) | 
						
							| 5 | 3 4 | mp1i | ⊢ ( ( 𝐴  ∈  𝑉  ∧  𝑥  ∈  ( 2o  ↑m  𝐴 ) )  →  ( ◡ 𝑥  “  { 1o } )  ∈  V ) | 
						
							| 6 |  | mptexg | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  ∈  V ) | 
						
							| 7 | 6 | adantr | ⊢ ( ( 𝐴  ∈  𝑉  ∧  𝑦  ∈  𝒫  𝐴 )  →  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  ∈  V ) | 
						
							| 8 |  | 2on | ⊢ 2o  ∈  On | 
						
							| 9 |  | elmapg | ⊢ ( ( 2o  ∈  On  ∧  𝐴  ∈  𝑉 )  →  ( 𝑥  ∈  ( 2o  ↑m  𝐴 )  ↔  𝑥 : 𝐴 ⟶ 2o ) ) | 
						
							| 10 | 8 9 | mpan | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝑥  ∈  ( 2o  ↑m  𝐴 )  ↔  𝑥 : 𝐴 ⟶ 2o ) ) | 
						
							| 11 | 10 | anbi1d | ⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝑥  ∈  ( 2o  ↑m  𝐴 )  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ↔  ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) ) ) ) | 
						
							| 12 |  | 1oex | ⊢ 1o  ∈  V | 
						
							| 13 | 12 | sucid | ⊢ 1o  ∈  suc  1o | 
						
							| 14 |  | df-2o | ⊢ 2o  =  suc  1o | 
						
							| 15 | 13 14 | eleqtrri | ⊢ 1o  ∈  2o | 
						
							| 16 |  | 0ex | ⊢ ∅  ∈  V | 
						
							| 17 | 16 | prid1 | ⊢ ∅  ∈  { ∅ ,  { ∅ } } | 
						
							| 18 |  | df2o2 | ⊢ 2o  =  { ∅ ,  { ∅ } } | 
						
							| 19 | 17 18 | eleqtrri | ⊢ ∅  ∈  2o | 
						
							| 20 | 15 19 | ifcli | ⊢ if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ )  ∈  2o | 
						
							| 21 | 20 | rgenw | ⊢ ∀ 𝑧  ∈  𝐴 if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ )  ∈  2o | 
						
							| 22 |  | eqid | ⊢ ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 23 | 22 | fmpt | ⊢ ( ∀ 𝑧  ∈  𝐴 if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ )  ∈  2o  ↔  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) : 𝐴 ⟶ 2o ) | 
						
							| 24 | 21 23 | mpbi | ⊢ ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) : 𝐴 ⟶ 2o | 
						
							| 25 |  | simpr | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ) | 
						
							| 26 | 25 | feq1d | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( 𝑥 : 𝐴 ⟶ 2o  ↔  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) : 𝐴 ⟶ 2o ) ) | 
						
							| 27 | 24 26 | mpbiri | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  𝑥 : 𝐴 ⟶ 2o ) | 
						
							| 28 |  | iftrue | ⊢ ( 𝑤  ∈  𝑦  →  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o ) | 
						
							| 29 |  | noel | ⊢ ¬  ∅  ∈  ∅ | 
						
							| 30 |  | iffalse | ⊢ ( ¬  𝑤  ∈  𝑦  →  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  ∅ ) | 
						
							| 31 | 30 | eqeq1d | ⊢ ( ¬  𝑤  ∈  𝑦  →  ( if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o  ↔  ∅  =  1o ) ) | 
						
							| 32 |  | 0lt1o | ⊢ ∅  ∈  1o | 
						
							| 33 |  | eleq2 | ⊢ ( ∅  =  1o  →  ( ∅  ∈  ∅  ↔  ∅  ∈  1o ) ) | 
						
							| 34 | 32 33 | mpbiri | ⊢ ( ∅  =  1o  →  ∅  ∈  ∅ ) | 
						
							| 35 | 31 34 | biimtrdi | ⊢ ( ¬  𝑤  ∈  𝑦  →  ( if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o  →  ∅  ∈  ∅ ) ) | 
						
							| 36 | 29 35 | mtoi | ⊢ ( ¬  𝑤  ∈  𝑦  →  ¬  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o ) | 
						
							| 37 | 36 | con4i | ⊢ ( if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o  →  𝑤  ∈  𝑦 ) | 
						
							| 38 | 28 37 | impbii | ⊢ ( 𝑤  ∈  𝑦  ↔  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o ) | 
						
							| 39 | 25 | fveq1d | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( 𝑥 ‘ 𝑤 )  =  ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ‘ 𝑤 ) ) | 
						
							| 40 |  | elequ1 | ⊢ ( 𝑧  =  𝑤  →  ( 𝑧  ∈  𝑦  ↔  𝑤  ∈  𝑦 ) ) | 
						
							| 41 | 40 | ifbid | ⊢ ( 𝑧  =  𝑤  →  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ )  =  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 42 | 12 16 | ifcli | ⊢ if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  ∈  V | 
						
							| 43 | 41 22 42 | fvmpt | ⊢ ( 𝑤  ∈  𝐴  →  ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ‘ 𝑤 )  =  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 44 | 39 43 | sylan9eq | ⊢ ( ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑥 ‘ 𝑤 )  =  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 45 | 44 | eqeq1d | ⊢ ( ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  ∧  𝑤  ∈  𝐴 )  →  ( ( 𝑥 ‘ 𝑤 )  =  1o  ↔  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o ) ) | 
						
							| 46 | 38 45 | bitr4id | ⊢ ( ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑤  ∈  𝑦  ↔  ( 𝑥 ‘ 𝑤 )  =  1o ) ) | 
						
							| 47 |  | fvex | ⊢ ( 𝑥 ‘ 𝑤 )  ∈  V | 
						
							| 48 | 47 | elsn | ⊢ ( ( 𝑥 ‘ 𝑤 )  ∈  { 1o }  ↔  ( 𝑥 ‘ 𝑤 )  =  1o ) | 
						
							| 49 | 46 48 | bitr4di | ⊢ ( ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑤  ∈  𝑦  ↔  ( 𝑥 ‘ 𝑤 )  ∈  { 1o } ) ) | 
						
							| 50 | 49 | pm5.32da | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( ( 𝑤  ∈  𝐴  ∧  𝑤  ∈  𝑦 )  ↔  ( 𝑤  ∈  𝐴  ∧  ( 𝑥 ‘ 𝑤 )  ∈  { 1o } ) ) ) | 
						
							| 51 |  | ssel | ⊢ ( 𝑦  ⊆  𝐴  →  ( 𝑤  ∈  𝑦  →  𝑤  ∈  𝐴 ) ) | 
						
							| 52 | 51 | adantr | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( 𝑤  ∈  𝑦  →  𝑤  ∈  𝐴 ) ) | 
						
							| 53 | 52 | pm4.71rd | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( 𝑤  ∈  𝑦  ↔  ( 𝑤  ∈  𝐴  ∧  𝑤  ∈  𝑦 ) ) ) | 
						
							| 54 |  | ffn | ⊢ ( 𝑥 : 𝐴 ⟶ 2o  →  𝑥  Fn  𝐴 ) | 
						
							| 55 |  | elpreima | ⊢ ( 𝑥  Fn  𝐴  →  ( 𝑤  ∈  ( ◡ 𝑥  “  { 1o } )  ↔  ( 𝑤  ∈  𝐴  ∧  ( 𝑥 ‘ 𝑤 )  ∈  { 1o } ) ) ) | 
						
							| 56 | 27 54 55 | 3syl | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( 𝑤  ∈  ( ◡ 𝑥  “  { 1o } )  ↔  ( 𝑤  ∈  𝐴  ∧  ( 𝑥 ‘ 𝑤 )  ∈  { 1o } ) ) ) | 
						
							| 57 | 50 53 56 | 3bitr4d | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( 𝑤  ∈  𝑦  ↔  𝑤  ∈  ( ◡ 𝑥  “  { 1o } ) ) ) | 
						
							| 58 | 57 | eqrdv | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  𝑦  =  ( ◡ 𝑥  “  { 1o } ) ) | 
						
							| 59 | 27 58 | jca | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  →  ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) ) ) | 
						
							| 60 |  | simpr | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  𝑦  =  ( ◡ 𝑥  “  { 1o } ) ) | 
						
							| 61 |  | cnvimass | ⊢ ( ◡ 𝑥  “  { 1o } )  ⊆  dom  𝑥 | 
						
							| 62 |  | fdm | ⊢ ( 𝑥 : 𝐴 ⟶ 2o  →  dom  𝑥  =  𝐴 ) | 
						
							| 63 | 62 | adantr | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  dom  𝑥  =  𝐴 ) | 
						
							| 64 | 61 63 | sseqtrid | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  ( ◡ 𝑥  “  { 1o } )  ⊆  𝐴 ) | 
						
							| 65 | 60 64 | eqsstrd | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  𝑦  ⊆  𝐴 ) | 
						
							| 66 |  | simplr | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  𝑦  =  ( ◡ 𝑥  “  { 1o } ) ) | 
						
							| 67 | 66 | eleq2d | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑤  ∈  𝑦  ↔  𝑤  ∈  ( ◡ 𝑥  “  { 1o } ) ) ) | 
						
							| 68 | 54 | adantr | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  𝑥  Fn  𝐴 ) | 
						
							| 69 |  | fnbrfvb | ⊢ ( ( 𝑥  Fn  𝐴  ∧  𝑤  ∈  𝐴 )  →  ( ( 𝑥 ‘ 𝑤 )  =  1o  ↔  𝑤 𝑥 1o ) ) | 
						
							| 70 | 68 69 | sylan | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( ( 𝑥 ‘ 𝑤 )  =  1o  ↔  𝑤 𝑥 1o ) ) | 
						
							| 71 |  | 1on | ⊢ 1o  ∈  On | 
						
							| 72 |  | vex | ⊢ 𝑤  ∈  V | 
						
							| 73 | 72 | eliniseg | ⊢ ( 1o  ∈  On  →  ( 𝑤  ∈  ( ◡ 𝑥  “  { 1o } )  ↔  𝑤 𝑥 1o ) ) | 
						
							| 74 | 71 73 | ax-mp | ⊢ ( 𝑤  ∈  ( ◡ 𝑥  “  { 1o } )  ↔  𝑤 𝑥 1o ) | 
						
							| 75 | 70 74 | bitr4di | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( ( 𝑥 ‘ 𝑤 )  =  1o  ↔  𝑤  ∈  ( ◡ 𝑥  “  { 1o } ) ) ) | 
						
							| 76 | 67 75 | bitr4d | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑤  ∈  𝑦  ↔  ( 𝑥 ‘ 𝑤 )  =  1o ) ) | 
						
							| 77 | 76 | biimpa | ⊢ ( ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  ∧  𝑤  ∈  𝑦 )  →  ( 𝑥 ‘ 𝑤 )  =  1o ) | 
						
							| 78 | 28 | adantl | ⊢ ( ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  ∧  𝑤  ∈  𝑦 )  →  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  1o ) | 
						
							| 79 | 77 78 | eqtr4d | ⊢ ( ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  ∧  𝑤  ∈  𝑦 )  →  ( 𝑥 ‘ 𝑤 )  =  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 80 |  | ffvelcdm | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑤  ∈  𝐴 )  →  ( 𝑥 ‘ 𝑤 )  ∈  2o ) | 
						
							| 81 | 80 | adantlr | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑥 ‘ 𝑤 )  ∈  2o ) | 
						
							| 82 |  | df2o3 | ⊢ 2o  =  { ∅ ,  1o } | 
						
							| 83 | 81 82 | eleqtrdi | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑥 ‘ 𝑤 )  ∈  { ∅ ,  1o } ) | 
						
							| 84 | 47 | elpr | ⊢ ( ( 𝑥 ‘ 𝑤 )  ∈  { ∅ ,  1o }  ↔  ( ( 𝑥 ‘ 𝑤 )  =  ∅  ∨  ( 𝑥 ‘ 𝑤 )  =  1o ) ) | 
						
							| 85 | 83 84 | sylib | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( ( 𝑥 ‘ 𝑤 )  =  ∅  ∨  ( 𝑥 ‘ 𝑤 )  =  1o ) ) | 
						
							| 86 | 85 | ord | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( ¬  ( 𝑥 ‘ 𝑤 )  =  ∅  →  ( 𝑥 ‘ 𝑤 )  =  1o ) ) | 
						
							| 87 | 86 76 | sylibrd | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( ¬  ( 𝑥 ‘ 𝑤 )  =  ∅  →  𝑤  ∈  𝑦 ) ) | 
						
							| 88 | 87 | con1d | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( ¬  𝑤  ∈  𝑦  →  ( 𝑥 ‘ 𝑤 )  =  ∅ ) ) | 
						
							| 89 | 88 | imp | ⊢ ( ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  ∧  ¬  𝑤  ∈  𝑦 )  →  ( 𝑥 ‘ 𝑤 )  =  ∅ ) | 
						
							| 90 | 30 | adantl | ⊢ ( ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  ∧  ¬  𝑤  ∈  𝑦 )  →  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ )  =  ∅ ) | 
						
							| 91 | 89 90 | eqtr4d | ⊢ ( ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  ∧  ¬  𝑤  ∈  𝑦 )  →  ( 𝑥 ‘ 𝑤 )  =  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 92 | 79 91 | pm2.61dan | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑥 ‘ 𝑤 )  =  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 93 | 43 | adantl | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ‘ 𝑤 )  =  if ( 𝑤  ∈  𝑦 ,  1o ,  ∅ ) ) | 
						
							| 94 | 92 93 | eqtr4d | ⊢ ( ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ∧  𝑤  ∈  𝐴 )  →  ( 𝑥 ‘ 𝑤 )  =  ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ‘ 𝑤 ) ) | 
						
							| 95 | 94 | ralrimiva | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  ∀ 𝑤  ∈  𝐴 ( 𝑥 ‘ 𝑤 )  =  ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ‘ 𝑤 ) ) | 
						
							| 96 |  | ffn | ⊢ ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) : 𝐴 ⟶ 2o  →  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  Fn  𝐴 ) | 
						
							| 97 | 24 96 | ax-mp | ⊢ ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  Fn  𝐴 | 
						
							| 98 |  | eqfnfv | ⊢ ( ( 𝑥  Fn  𝐴  ∧  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  Fn  𝐴 )  →  ( 𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  ↔  ∀ 𝑤  ∈  𝐴 ( 𝑥 ‘ 𝑤 )  =  ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ‘ 𝑤 ) ) ) | 
						
							| 99 | 68 97 98 | sylancl | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  ( 𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) )  ↔  ∀ 𝑤  ∈  𝐴 ( 𝑥 ‘ 𝑤 )  =  ( ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ‘ 𝑤 ) ) ) | 
						
							| 100 | 95 99 | mpbird | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ) | 
						
							| 101 | 65 100 | jca | ⊢ ( ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  →  ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ) ) | 
						
							| 102 | 59 101 | impbii | ⊢ ( ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  ↔  ( 𝑥 : 𝐴 ⟶ 2o  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) ) ) | 
						
							| 103 | 11 102 | bitr4di | ⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝑥  ∈  ( 2o  ↑m  𝐴 )  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ↔  ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ) ) ) | 
						
							| 104 |  | velpw | ⊢ ( 𝑦  ∈  𝒫  𝐴  ↔  𝑦  ⊆  𝐴 ) | 
						
							| 105 | 104 | anbi1i | ⊢ ( ( 𝑦  ∈  𝒫  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) )  ↔  ( 𝑦  ⊆  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ) ) | 
						
							| 106 | 103 105 | bitr4di | ⊢ ( 𝐴  ∈  𝑉  →  ( ( 𝑥  ∈  ( 2o  ↑m  𝐴 )  ∧  𝑦  =  ( ◡ 𝑥  “  { 1o } ) )  ↔  ( 𝑦  ∈  𝒫  𝐴  ∧  𝑥  =  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ) ) ) | 
						
							| 107 | 1 5 7 106 | f1ocnvd | ⊢ ( 𝐴  ∈  𝑉  →  ( 𝐹 : ( 2o  ↑m  𝐴 ) –1-1-onto→ 𝒫  𝐴  ∧  ◡ 𝐹  =  ( 𝑦  ∈  𝒫  𝐴  ↦  ( 𝑧  ∈  𝐴  ↦  if ( 𝑧  ∈  𝑦 ,  1o ,  ∅ ) ) ) ) ) |