| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lgsval.1 |  | 
						
							| 2 |  | lgsfcl2.z |  | 
						
							| 3 |  | 0z |  | 
						
							| 4 |  | 0le1 |  | 
						
							| 5 |  | fveq2 |  | 
						
							| 6 |  | abs0 |  | 
						
							| 7 | 5 6 | eqtrdi |  | 
						
							| 8 | 7 | breq1d |  | 
						
							| 9 | 8 2 | elrab2 |  | 
						
							| 10 | 3 4 9 | mpbir2an |  | 
						
							| 11 |  | 1z |  | 
						
							| 12 |  | 1le1 |  | 
						
							| 13 |  | fveq2 |  | 
						
							| 14 |  | abs1 |  | 
						
							| 15 | 13 14 | eqtrdi |  | 
						
							| 16 | 15 | breq1d |  | 
						
							| 17 | 16 2 | elrab2 |  | 
						
							| 18 | 11 12 17 | mpbir2an |  | 
						
							| 19 |  | neg1z |  | 
						
							| 20 |  | fveq2 |  | 
						
							| 21 |  | ax-1cn |  | 
						
							| 22 | 21 | absnegi |  | 
						
							| 23 | 22 14 | eqtri |  | 
						
							| 24 | 20 23 | eqtrdi |  | 
						
							| 25 | 24 | breq1d |  | 
						
							| 26 | 25 2 | elrab2 |  | 
						
							| 27 | 19 12 26 | mpbir2an |  | 
						
							| 28 | 18 27 | ifcli |  | 
						
							| 29 | 10 28 | ifcli |  | 
						
							| 30 | 29 | a1i |  | 
						
							| 31 |  | simpl1 |  | 
						
							| 32 | 31 | ad2antrr |  | 
						
							| 33 |  | simplr |  | 
						
							| 34 |  | simpr |  | 
						
							| 35 | 34 | neqned |  | 
						
							| 36 |  | eldifsn |  | 
						
							| 37 | 33 35 36 | sylanbrc |  | 
						
							| 38 | 2 | lgslem4 |  | 
						
							| 39 | 32 37 38 | syl2anc |  | 
						
							| 40 | 30 39 | ifclda |  | 
						
							| 41 |  | simpr |  | 
						
							| 42 |  | simpll2 |  | 
						
							| 43 |  | simpll3 |  | 
						
							| 44 |  | pczcl |  | 
						
							| 45 | 41 42 43 44 | syl12anc |  | 
						
							| 46 | 2 | ssrab3 |  | 
						
							| 47 |  | zsscn |  | 
						
							| 48 | 46 47 | sstri |  | 
						
							| 49 | 2 | lgslem3 |  | 
						
							| 50 | 48 49 18 | expcllem |  | 
						
							| 51 | 40 45 50 | syl2anc |  | 
						
							| 52 | 18 | a1i |  | 
						
							| 53 | 51 52 | ifclda |  | 
						
							| 54 | 53 1 | fmptd |  |