Proof of Theorem lcmneg
| Step | Hyp | Ref
 | Expression | 
| 1 |   | lcm0val 12233 | 
. . . . . . . 8
              lcm         | 
| 2 |   | znegcl 9357 | 
. . . . . . . . 9
                   | 
| 3 |   | lcm0val 12233 | 
. . . . . . . . 9
       
        lcm
        | 
| 4 | 2, 3 | syl 14 | 
. . . . . . . 8
               lcm         | 
| 5 | 1, 4 | eqtr4d 2232 | 
. . . . . . 7
              lcm          lcm
    | 
| 6 | 5 | ad2antlr 489 | 
. . . . . 6
                              
   lcm          lcm
    | 
| 7 |   | oveq2 5930 | 
. . . . . . . 8
              lcm         lcm     | 
| 8 |   | oveq2 5930 | 
. . . . . . . 8
               lcm          lcm     | 
| 9 | 7, 8 | eqeq12d 2211 | 
. . . . . . 7
               lcm          lcm         lcm          lcm      | 
| 10 | 9 | adantl 277 | 
. . . . . 6
                              
    lcm          lcm
        lcm          lcm      | 
| 11 | 6, 10 | mpbird 167 | 
. . . . 5
                              
   lcm          lcm     | 
| 12 |   | lcmcom 12232 | 
. . . . . . 7
               
        lcm         lcm     | 
| 13 |   | lcmcom 12232 | 
. . . . . . . 8
                         lcm           lcm     | 
| 14 | 2, 13 | sylan2 286 | 
. . . . . . 7
               
        lcm           lcm     | 
| 15 | 12, 14 | eqeq12d 2211 | 
. . . . . 6
               
         lcm         lcm      
   lcm          lcm      | 
| 16 | 15 | adantr 276 | 
. . . . 5
                              
    lcm         lcm      
   lcm          lcm      | 
| 17 | 11, 16 | mpbird 167 | 
. . . 4
                              
   lcm         lcm      | 
| 18 |   | neg0 8272 | 
. . . . . . . 8
         | 
| 19 | 18 | oveq2i 5933 | 
. . . . . . 7
     lcm          lcm    | 
| 20 | 19 | eqcomi 2200 | 
. . . . . 6
     lcm         lcm     | 
| 21 |   | oveq2 5930 | 
. . . . . 6
              lcm         lcm     | 
| 22 |   | negeq 8219 | 
. . . . . . 7
                    | 
| 23 | 22 | oveq2d 5938 | 
. . . . . 6
              lcm          lcm      | 
| 24 | 20, 21, 23 | 3eqtr4a 2255 | 
. . . . 5
              lcm         lcm      | 
| 25 | 24 | adantl 277 | 
. . . 4
                              
   lcm         lcm      | 
| 26 | 17, 25 | jaodan 798 | 
. . 3
                                            lcm         lcm      | 
| 27 |   | dvdslcm 12237 | 
. . . . . . . 8
                             
lcm               lcm       | 
| 28 | 2, 27 | sylan2 286 | 
. . . . . . 7
               
             lcm               lcm       | 
| 29 |   | simpr 110 | 
. . . . . . . . 9
               
            | 
| 30 |   | lcmcl 12240 | 
. . . . . . . . . . 11
                         lcm          | 
| 31 | 2, 30 | sylan2 286 | 
. . . . . . . . . 10
               
        lcm          | 
| 32 | 31 | nn0zd 9446 | 
. . . . . . . . 9
               
        lcm          | 
| 33 |   | negdvdsb 11972 | 
. . . . . . . . 9
              
lcm                    lcm      
       
lcm       | 
| 34 | 29, 32, 33 | syl2anc 411 | 
. . . . . . . 8
               
             lcm      
       
lcm       | 
| 35 | 34 | anbi2d 464 | 
. . . . . . 7
               
             
lcm              lcm                lcm               lcm        | 
| 36 | 28, 35 | mpbird 167 | 
. . . . . 6
               
             lcm              lcm       | 
| 37 | 36 | adantr 276 | 
. . . . 5
                                                  
lcm              lcm       | 
| 38 |   | zcn 9331 | 
. . . . . . . . . . . . 13
                  | 
| 39 | 38 | negeq0d 8329 | 
. . . . . . . . . . . 12
               
   
         | 
| 40 | 39 | orbi2d 791 | 
. . . . . . . . . . 11
                                                 | 
| 41 | 40 | notbid 668 | 
. . . . . . . . . 10
                                 
                   | 
| 42 | 41 | biimpa 296 | 
. . . . . . . . 9
                                     
               | 
| 43 | 42 | adantll 476 | 
. . . . . . . 8
                                            
                  | 
| 44 |   | lcmn0cl 12236 | 
. . . . . . . . 9
               
                                lcm          | 
| 45 | 2, 44 | sylanl2 403 | 
. . . . . . . 8
                                               lcm          | 
| 46 | 43, 45 | syldan 282 | 
. . . . . . 7
                                              lcm          | 
| 47 |   | simpl 109 | 
. . . . . . 7
                                                            | 
| 48 |   | 3anass 984 | 
. . . . . . 7
       lcm              
            
    lcm                             | 
| 49 | 46, 47, 48 | sylanbrc 417 | 
. . . . . 6
                                               lcm                      
    | 
| 50 |   | simpr 110 | 
. . . . . 6
                                            
                 | 
| 51 |   | lcmledvds 12238 | 
. . . . . 6
        lcm              
                 
       
                 lcm              lcm           lcm         lcm       | 
| 52 | 49, 50, 51 | syl2anc 411 | 
. . . . 5
                                                    lcm      
       lcm           lcm     
   lcm       | 
| 53 | 37, 52 | mpd 13 | 
. . . 4
                                              lcm     
   lcm      | 
| 54 |   | dvdslcm 12237 | 
. . . . . 6
               
             lcm             lcm      | 
| 55 | 54 | adantr 276 | 
. . . . 5
                                                  
lcm       
     lcm      | 
| 56 |   | simplr 528 | 
. . . . . . . 8
                                                  | 
| 57 |   | lcmn0cl 12236 | 
. . . . . . . . 9
                                              lcm         | 
| 58 | 57 | nnzd 9447 | 
. . . . . . . 8
                                              lcm         | 
| 59 |   | negdvdsb 11972 | 
. . . . . . . 8
              
lcm                   lcm              lcm      | 
| 60 | 56, 58, 59 | syl2anc 411 | 
. . . . . . 7
                                                  
lcm              lcm      | 
| 61 | 60 | anbi2d 464 | 
. . . . . 6
                                                    lcm     
       lcm      
        lcm              lcm       | 
| 62 |   | lcmledvds 12238 | 
. . . . . . . . . 10
        lcm             
                  
                          lcm              lcm      
   lcm          lcm      | 
| 63 | 62 | ex 115 | 
. . . . . . . . 9
       lcm                                                 
         lcm     
       
lcm      
   lcm          lcm       | 
| 64 | 2, 63 | syl3an3 1284 | 
. . . . . . . 8
       lcm                                                
         lcm     
       
lcm      
   lcm          lcm       | 
| 65 | 64 | 3expib 1208 | 
. . . . . . 7
      lcm         
     
                                  
         lcm     
       
lcm      
   lcm          lcm        | 
| 66 | 57, 47, 43, 65 | syl3c 63 | 
. . . . . 6
                                                    lcm     
       
lcm      
   lcm          lcm      | 
| 67 | 61, 66 | sylbid 150 | 
. . . . 5
                                                    lcm     
       lcm          lcm      
   lcm      | 
| 68 | 55, 67 | mpd 13 | 
. . . 4
                                              lcm      
   lcm     | 
| 69 |   | lcmcl 12240 | 
. . . . . . 7
               
        lcm         | 
| 70 | 69 | nn0red 9303 | 
. . . . . 6
               
        lcm         | 
| 71 | 30 | nn0red 9303 | 
. . . . . . 7
                         lcm          | 
| 72 | 2, 71 | sylan2 286 | 
. . . . . 6
               
        lcm          | 
| 73 | 70, 72 | letri3d 8142 | 
. . . . 5
               
         lcm         lcm      
    lcm         lcm         
lcm          lcm       | 
| 74 | 73 | adantr 276 | 
. . . 4
                                               lcm         lcm      
    lcm         lcm         
lcm          lcm       | 
| 75 | 53, 68, 74 | mpbir2and 946 | 
. . 3
                                              lcm         lcm      | 
| 76 |   | lcmmndc 12230 | 
. . . 4
               
     DECID                  | 
| 77 |   | exmiddc 837 | 
. . . 4
   DECID                                          
       
       | 
| 78 | 76, 77 | syl 14 | 
. . 3
               
                            
       
       | 
| 79 | 26, 75, 78 | mpjaodan 799 | 
. 2
               
        lcm         lcm      | 
| 80 | 79 | eqcomd 2202 | 
1
               
        lcm          lcm     |