| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 4sq.1 |  | 
						
							| 2 |  | 4sq.2 |  | 
						
							| 3 |  | 4sq.3 |  | 
						
							| 4 |  | 4sq.4 |  | 
						
							| 5 |  | 4sq.5 |  | 
						
							| 6 |  | 4sq.6 |  | 
						
							| 7 |  | 4sq.7 |  | 
						
							| 8 |  | eqid |  | 
						
							| 9 |  | eqid |  | 
						
							| 10 | 1 2 3 4 8 9 | 4sqlem12 |  | 
						
							| 11 |  | simplrl |  | 
						
							| 12 |  | elfznn |  | 
						
							| 13 | 11 12 | syl |  | 
						
							| 14 |  | simpr |  | 
						
							| 15 |  | abs1 |  | 
						
							| 16 | 15 | oveq1i |  | 
						
							| 17 |  | sq1 |  | 
						
							| 18 | 16 17 | eqtri |  | 
						
							| 19 | 18 | oveq2i |  | 
						
							| 20 |  | simplrr |  | 
						
							| 21 |  | 1z |  | 
						
							| 22 |  | zgz |  | 
						
							| 23 | 21 22 | ax-mp |  | 
						
							| 24 | 1 | 4sqlem4a |  | 
						
							| 25 | 20 23 24 | sylancl |  | 
						
							| 26 | 19 25 | eqeltrrid |  | 
						
							| 27 | 14 26 | eqeltrrd |  | 
						
							| 28 |  | oveq1 |  | 
						
							| 29 | 28 | eleq1d |  | 
						
							| 30 | 29 6 | elrab2 |  | 
						
							| 31 | 13 27 30 | sylanbrc |  | 
						
							| 32 | 31 | ne0d |  | 
						
							| 33 | 6 | ssrab3 |  | 
						
							| 34 |  | nnuz |  | 
						
							| 35 | 33 34 | sseqtri |  | 
						
							| 36 |  | infssuzcl |  | 
						
							| 37 | 35 32 36 | sylancr |  | 
						
							| 38 | 7 37 | eqeltrid |  | 
						
							| 39 | 33 38 | sselid |  | 
						
							| 40 | 39 | nnred |  | 
						
							| 41 | 13 | nnred |  | 
						
							| 42 | 4 | ad2antrr |  | 
						
							| 43 |  | prmnn |  | 
						
							| 44 | 42 43 | syl |  | 
						
							| 45 | 44 | nnred |  | 
						
							| 46 |  | infssuzle |  | 
						
							| 47 | 35 31 46 | sylancr |  | 
						
							| 48 | 7 47 | eqbrtrid |  | 
						
							| 49 |  | prmz |  | 
						
							| 50 | 42 49 | syl |  | 
						
							| 51 |  | elfzm11 |  | 
						
							| 52 | 21 50 51 | sylancr |  | 
						
							| 53 | 11 52 | mpbid |  | 
						
							| 54 | 53 | simp3d |  | 
						
							| 55 | 40 41 45 48 54 | lelttrd |  | 
						
							| 56 | 32 55 | jca |  | 
						
							| 57 | 56 | ex |  | 
						
							| 58 | 57 | rexlimdvva |  | 
						
							| 59 | 10 58 | mpd |  |