| Step | Hyp | Ref
| Expression |
| 1 | | peano4nninf.s |
. . 3

ℕ∞               |
| 2 | 1 | nnsf 15649 |
. 2
 ℕ∞ ℕ∞ |
| 3 | | fveq1 5557 |
. . . . . . . . . . 11
           |
| 4 | | fveq1 5557 |
. . . . . . . . . . 11
           |
| 5 | 3, 4 | sseq12d 3214 |
. . . . . . . . . 10
             
       |
| 6 | 5 | ralbidv 2497 |
. . . . . . . . 9
  
                    |
| 7 | | df-nninf 7186 |
. . . . . . . . 9
ℕ∞   
           |
| 8 | 6, 7 | elrab2 2923 |
. . . . . . . 8
 ℕ∞    
           |
| 9 | 8 | simplbi 274 |
. . . . . . 7
 ℕ∞     |
| 10 | | elmapfn 6730 |
. . . . . . 7
  
  |
| 11 | 9, 10 | syl 14 |
. . . . . 6
 ℕ∞   |
| 12 | 11 | ad2antrr 488 |
. . . . 5
  
ℕ∞
ℕ∞            |
| 13 | | fveq1 5557 |
. . . . . . . . . . 11
           |
| 14 | | fveq1 5557 |
. . . . . . . . . . 11
           |
| 15 | 13, 14 | sseq12d 3214 |
. . . . . . . . . 10
             
       |
| 16 | 15 | ralbidv 2497 |
. . . . . . . . 9
  
                    |
| 17 | 16, 7 | elrab2 2923 |
. . . . . . . 8
 ℕ∞    
           |
| 18 | 17 | simplbi 274 |
. . . . . . 7
 ℕ∞     |
| 19 | | elmapfn 6730 |
. . . . . . 7
  
  |
| 20 | 18, 19 | syl 14 |
. . . . . 6
 ℕ∞   |
| 21 | 20 | ad2antlr 489 |
. . . . 5
  
ℕ∞
ℕ∞            |
| 22 | | simplr 528 |
. . . . . . 7
    ℕ∞
ℕ∞                     |
| 23 | 22 | fveq1d 5560 |
. . . . . 6
    ℕ∞
ℕ∞                             |
| 24 | | fveq1 5557 |
. . . . . . . . . . . 12
             |
| 25 | 24 | ifeq2d 3579 |
. . . . . . . . . . 11
                       |
| 26 | 25 | mpteq2dv 4124 |
. . . . . . . . . 10
                           |
| 27 | | omex 4629 |
. . . . . . . . . . 11
 |
| 28 | 27 | mptex 5788 |
. . . . . . . . . 10
             |
| 29 | 26, 1, 28 | fvmpt 5638 |
. . . . . . . . 9
 ℕ∞                   |
| 30 | 29 | ad3antrrr 492 |
. . . . . . . 8
    ℕ∞
ℕ∞                             |
| 31 | | simpr 110 |
. . . . . . . . . 10
     ℕ∞
ℕ∞              |
| 32 | 31 | eqeq1d 2205 |
. . . . . . . . 9
     ℕ∞
ℕ∞            
   |
| 33 | 31 | unieqd 3850 |
. . . . . . . . . 10
     ℕ∞
ℕ∞            
   |
| 34 | 33 | fveq2d 5562 |
. . . . . . . . 9
     ℕ∞
ℕ∞                        |
| 35 | 32, 34 | ifbieq2d 3585 |
. . . . . . . 8
     ℕ∞
ℕ∞                                  |
| 36 | | peano2 4631 |
. . . . . . . . 9

  |
| 37 | 36 | adantl 277 |
. . . . . . . 8
    ℕ∞
ℕ∞          
  |
| 38 | | 1lt2o 6500 |
. . . . . . . . . 10
 |
| 39 | 38 | a1i 9 |
. . . . . . . . 9
    ℕ∞
ℕ∞             |
| 40 | | nninff 7188 |
. . . . . . . . . . 11
 ℕ∞       |
| 41 | 40 | ad3antrrr 492 |
. . . . . . . . . 10
    ℕ∞
ℕ∞                 |
| 42 | | nnpredcl 4659 |
. . . . . . . . . . 11
    |
| 43 | 37, 42 | syl 14 |
. . . . . . . . . 10
    ℕ∞
ℕ∞           
  |
| 44 | 41, 43 | ffvelcdmd 5698 |
. . . . . . . . 9
    ℕ∞
ℕ∞                  |
| 45 | | nndceq0 4654 |
. . . . . . . . . 10
 DECID   |
| 46 | 37, 45 | syl 14 |
. . . . . . . . 9
    ℕ∞
ℕ∞          
DECID   |
| 47 | 39, 44, 46 | ifcldcd 3597 |
. . . . . . . 8
    ℕ∞
ℕ∞                       |
| 48 | 30, 35, 37, 47 | fvmptd 5642 |
. . . . . . 7
    ℕ∞
ℕ∞                               |
| 49 | | peano3 4632 |
. . . . . . . . . 10
   |
| 50 | 49 | adantl 277 |
. . . . . . . . 9
    ℕ∞
ℕ∞             |
| 51 | 50 | neneqd 2388 |
. . . . . . . 8
    ℕ∞
ℕ∞          
  |
| 52 | 51 | iffalsed 3571 |
. . . . . . 7
    ℕ∞
ℕ∞                            |
| 53 | | nnord 4648 |
. . . . . . . . . . 11
   |
| 54 | | ordtr 4413 |
. . . . . . . . . . 11

  |
| 55 | 53, 54 | syl 14 |
. . . . . . . . . 10
   |
| 56 | | unisucg 4449 |
. . . . . . . . . 10
 
    |
| 57 | 55, 56 | mpbid 147 |
. . . . . . . . 9
 
  |
| 58 | 57 | fveq2d 5562 |
. . . . . . . 8
            |
| 59 | 58 | adantl 277 |
. . . . . . 7
    ℕ∞
ℕ∞                      |
| 60 | 48, 52, 59 | 3eqtrd 2233 |
. . . . . 6
    ℕ∞
ℕ∞                         |
| 61 | | fveq1 5557 |
. . . . . . . . . . . 12
             |
| 62 | 61 | ifeq2d 3579 |
. . . . . . . . . . 11
                       |
| 63 | 62 | mpteq2dv 4124 |
. . . . . . . . . 10
                           |
| 64 | 27 | mptex 5788 |
. . . . . . . . . 10
             |
| 65 | 63, 1, 64 | fvmpt 5638 |
. . . . . . . . 9
 ℕ∞                   |
| 66 | 65 | ad3antlr 493 |
. . . . . . . 8
    ℕ∞
ℕ∞                             |
| 67 | 33 | fveq2d 5562 |
. . . . . . . . 9
     ℕ∞
ℕ∞                        |
| 68 | 32, 67 | ifbieq2d 3585 |
. . . . . . . 8
     ℕ∞
ℕ∞                                  |
| 69 | | nninff 7188 |
. . . . . . . . . . 11
 ℕ∞       |
| 70 | 69 | ad3antlr 493 |
. . . . . . . . . 10
    ℕ∞
ℕ∞                 |
| 71 | 70, 43 | ffvelcdmd 5698 |
. . . . . . . . 9
    ℕ∞
ℕ∞                  |
| 72 | 39, 71, 46 | ifcldcd 3597 |
. . . . . . . 8
    ℕ∞
ℕ∞                       |
| 73 | 66, 68, 37, 72 | fvmptd 5642 |
. . . . . . 7
    ℕ∞
ℕ∞                               |
| 74 | 51 | iffalsed 3571 |
. . . . . . 7
    ℕ∞
ℕ∞                            |
| 75 | 57 | fveq2d 5562 |
. . . . . . . 8
            |
| 76 | 75 | adantl 277 |
. . . . . . 7
    ℕ∞
ℕ∞                      |
| 77 | 73, 74, 76 | 3eqtrd 2233 |
. . . . . 6
    ℕ∞
ℕ∞                         |
| 78 | 23, 60, 77 | 3eqtr3d 2237 |
. . . . 5
    ℕ∞
ℕ∞                     |
| 79 | 12, 21, 78 | eqfnfvd 5662 |
. . . 4
  
ℕ∞
ℕ∞            |
| 80 | 79 | ex 115 |
. . 3
 
ℕ∞
ℕ∞
            |
| 81 | 80 | rgen2a 2551 |
. 2
 ℕ∞ 
ℕ∞            |
| 82 | | dff13 5815 |
. 2
  ℕ∞ ℕ∞
  ℕ∞ ℕ∞ 
ℕ∞ 
ℕ∞              |
| 83 | 2, 81, 82 | mpbir2an 944 |
1
 ℕ∞ ℕ∞ |