| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lgsval4.1 |  | 
						
							| 2 |  | simpl |  | 
						
							| 3 |  | nnz |  | 
						
							| 4 | 3 | adantl |  | 
						
							| 5 |  | nnne0 |  | 
						
							| 6 | 5 | adantl |  | 
						
							| 7 | 1 | lgsval4 |  | 
						
							| 8 | 2 4 6 7 | syl3anc |  | 
						
							| 9 |  | nngt0 |  | 
						
							| 10 | 9 | adantl |  | 
						
							| 11 |  | 0re |  | 
						
							| 12 |  | nnre |  | 
						
							| 13 | 12 | adantl |  | 
						
							| 14 |  | ltnsym |  | 
						
							| 15 | 11 13 14 | sylancr |  | 
						
							| 16 | 10 15 | mpd |  | 
						
							| 17 | 16 | intnanrd |  | 
						
							| 18 | 17 | iffalsed |  | 
						
							| 19 |  | nnnn0 |  | 
						
							| 20 | 19 | adantl |  | 
						
							| 21 | 20 | nn0ge0d |  | 
						
							| 22 | 13 21 | absidd |  | 
						
							| 23 | 22 | fveq2d |  | 
						
							| 24 | 18 23 | oveq12d |  | 
						
							| 25 |  | simpr |  | 
						
							| 26 |  | nnuz |  | 
						
							| 27 | 25 26 | eleqtrdi |  | 
						
							| 28 | 1 | lgsfcl3 |  | 
						
							| 29 | 2 4 6 28 | syl3anc |  | 
						
							| 30 |  | elfznn |  | 
						
							| 31 |  | ffvelcdm |  | 
						
							| 32 | 29 30 31 | syl2an |  | 
						
							| 33 |  | zmulcl |  | 
						
							| 34 | 33 | adantl |  | 
						
							| 35 | 27 32 34 | seqcl |  | 
						
							| 36 | 35 | zcnd |  | 
						
							| 37 | 36 | mullidd |  | 
						
							| 38 | 8 24 37 | 3eqtrd |  |