Step | Hyp | Ref
| Expression |
1 | | nfra1 2941 |
. 2
  
             |
2 | | eqeq1 2626 |
. . . . . . . 8
     
       |
3 | 2 | rexbidv 3052 |
. . . . . . 7
  
   
        |
4 | 3 | 2rexbidv 3057 |
. . . . . 6
  
      
         |
5 | 4 | cbvralv 3171 |
. . . . 5
 
           
      
        |
6 | | 6nn 11189 |
. . . . . . . . 9
 |
7 | 6 | nnzi 11401 |
. . . . . . . 8
 |
8 | 7 | a1i 11 |
. . . . . . 7
  Even    |
9 | | evenz 41543 |
. . . . . . . . 9
 Even   |
10 | | 2z 11409 |
. . . . . . . . . 10
 |
11 | 10 | a1i 11 |
. . . . . . . . 9
 Even   |
12 | 9, 11 | zaddcld 11486 |
. . . . . . . 8
 Even     |
13 | 12 | adantr 481 |
. . . . . . 7
  Even      |
14 | | 4cn 11098 |
. . . . . . . . . 10
 |
15 | | 2cn 11091 |
. . . . . . . . . 10
 |
16 | | 4p2e6 11162 |
. . . . . . . . . . 11
   |
17 | 16 | eqcomi 2631 |
. . . . . . . . . 10
   |
18 | 14, 15, 17 | mvrraddi 10298 |
. . . . . . . . 9
   |
19 | | 2p2e4 11144 |
. . . . . . . . . 10
   |
20 | | 2evenALTV 41603 |
. . . . . . . . . . 11
Even |
21 | | evenltle 41626 |
. . . . . . . . . . 11
  Even Even 
    |
22 | 20, 21 | mp3an2 1412 |
. . . . . . . . . 10
  Even      |
23 | 19, 22 | syl5eqbrr 4689 |
. . . . . . . . 9
  Even    |
24 | 18, 23 | syl5eqbr 4688 |
. . . . . . . 8
  Even      |
25 | | 6re 11101 |
. . . . . . . . . . . 12
 |
26 | 25 | a1i 11 |
. . . . . . . . . . 11
 Even   |
27 | | 2re 11090 |
. . . . . . . . . . . 12
 |
28 | 27 | a1i 11 |
. . . . . . . . . . 11
 Even   |
29 | 9 | zred 11482 |
. . . . . . . . . . 11
 Even   |
30 | 26, 28, 29 | 3jca 1242 |
. . . . . . . . . 10
 Even     |
31 | 30 | adantr 481 |
. . . . . . . . 9
  Even  
   |
32 | | lesubadd 10500 |
. . . . . . . . 9
 
   
     |
33 | 31, 32 | syl 17 |
. . . . . . . 8
  Even    
     |
34 | 24, 33 | mpbid 222 |
. . . . . . 7
  Even      |
35 | | eluz2 11693 |
. . . . . . 7
               |
36 | 8, 13, 34, 35 | syl3anbrc 1246 |
. . . . . 6
  Even          |
37 | | eqeq1 2626 |
. . . . . . . . 9
       
         |
38 | 37 | rexbidv 3052 |
. . . . . . . 8
    
   
          |
39 | 38 | 2rexbidv 3057 |
. . . . . . 7
    
      
           |
40 | 39 | rspcv 3305 |
. . . . . 6
      
 
                        |
41 | 36, 40 | syl 17 |
. . . . 5
  Even   
                        |
42 | 5, 41 | syl5bi 232 |
. . . 4
  Even   
                        |
43 | | nfv 1843 |
. . . . 5
   Even   |
44 | | nfre1 3005 |
. . . . 5
  
    |
45 | | nfv 1843 |
. . . . . . 7
    Even
   |
46 | | nfcv 2764 |
. . . . . . . 8
   |
47 | | nfre1 3005 |
. . . . . . . 8
      |
48 | 46, 47 | nfrex 3007 |
. . . . . . 7
       |
49 | | simplrl 800 |
. . . . . . . . . . . . 13
    Even
    
  |
50 | | simplrr 801 |
. . . . . . . . . . . . 13
    Even
    
  |
51 | | simpr 477 |
. . . . . . . . . . . . 13
    Even
    
  |
52 | 49, 50, 51 | 3jca 1242 |
. . . . . . . . . . . 12
    Even
    

   |
53 | 52 | adantr 481 |
. . . . . . . . . . 11
     Even
 
 
 
          |
54 | | simp-4l 806 |
. . . . . . . . . . 11
     Even
 
 
 
      Even  |
55 | | simpr 477 |
. . . . . . . . . . 11
     Even
 
 
 
              |
56 | | mogoldbblem 41629 |
. . . . . . . . . . . 12
    Even       
      |
57 | | oveq1 6657 |
. . . . . . . . . . . . . 14
       |
58 | 57 | eqeq2d 2632 |
. . . . . . . . . . . . 13
   
     |
59 | | oveq2 6658 |
. . . . . . . . . . . . . 14
       |
60 | 59 | eqeq2d 2632 |
. . . . . . . . . . . . 13
   
     |
61 | 58, 60 | cbvrex2v 3180 |
. . . . . . . . . . . 12
     
     |
62 | 56, 61 | sylibr 224 |
. . . . . . . . . . 11
    Even       
      |
63 | 53, 54, 55, 62 | syl3anc 1326 |
. . . . . . . . . 10
     Even
 
 
 
            |
64 | 63 | exp31 630 |
. . . . . . . . 9
   Even  
 

               |
65 | 64 | rexlimdv 3030 |
. . . . . . . 8
   Even  
 
 
     
       |
66 | 65 | expr 643 |
. . . . . . 7
   Even 
          
       |
67 | 45, 48, 66 | rexlimd 3026 |
. . . . . 6
   Even 
                 |
68 | 67 | ex 450 |
. . . . 5
  Even                    |
69 | 43, 44, 68 | rexlimd 3026 |
. . . 4
  Even   
               |
70 | 42, 69 | syldc 48 |
. . 3
 
              Even  
      |
71 | 70 | expd 452 |
. 2
 
             Even
         |
72 | 1, 71 | ralrimi 2957 |
1
 
             Even         |