| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 0re |  |-  0 e. RR | 
						
							| 2 |  | lttri4 |  |-  ( ( _i e. RR /\ 0 e. RR ) -> ( _i < 0 \/ _i = 0 \/ 0 < _i ) ) | 
						
							| 3 | 1 2 | mpan2 |  |-  ( _i e. RR -> ( _i < 0 \/ _i = 0 \/ 0 < _i ) ) | 
						
							| 4 |  | reneg1lt0 |  |-  ( 0 -R 1 ) < 0 | 
						
							| 5 |  | 1re |  |-  1 e. RR | 
						
							| 6 |  | rernegcl |  |-  ( 1 e. RR -> ( 0 -R 1 ) e. RR ) | 
						
							| 7 | 5 6 | ax-mp |  |-  ( 0 -R 1 ) e. RR | 
						
							| 8 | 7 1 | ltnsymi |  |-  ( ( 0 -R 1 ) < 0 -> -. 0 < ( 0 -R 1 ) ) | 
						
							| 9 | 4 8 | ax-mp |  |-  -. 0 < ( 0 -R 1 ) | 
						
							| 10 |  | relt0neg1 |  |-  ( _i e. RR -> ( _i < 0 <-> 0 < ( 0 -R _i ) ) ) | 
						
							| 11 |  | rernegcl |  |-  ( _i e. RR -> ( 0 -R _i ) e. RR ) | 
						
							| 12 |  | mulgt0 |  |-  ( ( ( ( 0 -R _i ) e. RR /\ 0 < ( 0 -R _i ) ) /\ ( ( 0 -R _i ) e. RR /\ 0 < ( 0 -R _i ) ) ) -> 0 < ( ( 0 -R _i ) x. ( 0 -R _i ) ) ) | 
						
							| 13 | 12 | anidms |  |-  ( ( ( 0 -R _i ) e. RR /\ 0 < ( 0 -R _i ) ) -> 0 < ( ( 0 -R _i ) x. ( 0 -R _i ) ) ) | 
						
							| 14 | 11 13 | sylan |  |-  ( ( _i e. RR /\ 0 < ( 0 -R _i ) ) -> 0 < ( ( 0 -R _i ) x. ( 0 -R _i ) ) ) | 
						
							| 15 |  | id |  |-  ( _i e. RR -> _i e. RR ) | 
						
							| 16 | 11 15 | remulneg2d |  |-  ( _i e. RR -> ( ( 0 -R _i ) x. ( 0 -R _i ) ) = ( 0 -R ( ( 0 -R _i ) x. _i ) ) ) | 
						
							| 17 | 15 15 | remulcld |  |-  ( _i e. RR -> ( _i x. _i ) e. RR ) | 
						
							| 18 | 15 17 | remulcld |  |-  ( _i e. RR -> ( _i x. ( _i x. _i ) ) e. RR ) | 
						
							| 19 |  | ipiiie0 |  |-  ( _i + ( _i x. ( _i x. _i ) ) ) = 0 | 
						
							| 20 |  | renegadd |  |-  ( ( _i e. RR /\ ( _i x. ( _i x. _i ) ) e. RR ) -> ( ( 0 -R _i ) = ( _i x. ( _i x. _i ) ) <-> ( _i + ( _i x. ( _i x. _i ) ) ) = 0 ) ) | 
						
							| 21 | 19 20 | mpbiri |  |-  ( ( _i e. RR /\ ( _i x. ( _i x. _i ) ) e. RR ) -> ( 0 -R _i ) = ( _i x. ( _i x. _i ) ) ) | 
						
							| 22 | 18 21 | mpdan |  |-  ( _i e. RR -> ( 0 -R _i ) = ( _i x. ( _i x. _i ) ) ) | 
						
							| 23 | 22 | oveq1d |  |-  ( _i e. RR -> ( ( 0 -R _i ) x. _i ) = ( ( _i x. ( _i x. _i ) ) x. _i ) ) | 
						
							| 24 |  | ax-icn |  |-  _i e. CC | 
						
							| 25 | 24 24 24 | mulassi |  |-  ( ( _i x. _i ) x. _i ) = ( _i x. ( _i x. _i ) ) | 
						
							| 26 | 25 | oveq1i |  |-  ( ( ( _i x. _i ) x. _i ) x. _i ) = ( ( _i x. ( _i x. _i ) ) x. _i ) | 
						
							| 27 | 24 24 | mulcli |  |-  ( _i x. _i ) e. CC | 
						
							| 28 | 27 24 24 | mulassi |  |-  ( ( ( _i x. _i ) x. _i ) x. _i ) = ( ( _i x. _i ) x. ( _i x. _i ) ) | 
						
							| 29 | 26 28 | eqtr3i |  |-  ( ( _i x. ( _i x. _i ) ) x. _i ) = ( ( _i x. _i ) x. ( _i x. _i ) ) | 
						
							| 30 | 29 | a1i |  |-  ( _i e. RR -> ( ( _i x. ( _i x. _i ) ) x. _i ) = ( ( _i x. _i ) x. ( _i x. _i ) ) ) | 
						
							| 31 |  | rei4 |  |-  ( ( _i x. _i ) x. ( _i x. _i ) ) = 1 | 
						
							| 32 | 31 | a1i |  |-  ( _i e. RR -> ( ( _i x. _i ) x. ( _i x. _i ) ) = 1 ) | 
						
							| 33 | 23 30 32 | 3eqtrd |  |-  ( _i e. RR -> ( ( 0 -R _i ) x. _i ) = 1 ) | 
						
							| 34 | 33 | oveq2d |  |-  ( _i e. RR -> ( 0 -R ( ( 0 -R _i ) x. _i ) ) = ( 0 -R 1 ) ) | 
						
							| 35 | 16 34 | eqtrd |  |-  ( _i e. RR -> ( ( 0 -R _i ) x. ( 0 -R _i ) ) = ( 0 -R 1 ) ) | 
						
							| 36 | 35 | breq2d |  |-  ( _i e. RR -> ( 0 < ( ( 0 -R _i ) x. ( 0 -R _i ) ) <-> 0 < ( 0 -R 1 ) ) ) | 
						
							| 37 | 36 | adantr |  |-  ( ( _i e. RR /\ 0 < ( 0 -R _i ) ) -> ( 0 < ( ( 0 -R _i ) x. ( 0 -R _i ) ) <-> 0 < ( 0 -R 1 ) ) ) | 
						
							| 38 | 14 37 | mpbid |  |-  ( ( _i e. RR /\ 0 < ( 0 -R _i ) ) -> 0 < ( 0 -R 1 ) ) | 
						
							| 39 | 38 | ex |  |-  ( _i e. RR -> ( 0 < ( 0 -R _i ) -> 0 < ( 0 -R 1 ) ) ) | 
						
							| 40 | 10 39 | sylbid |  |-  ( _i e. RR -> ( _i < 0 -> 0 < ( 0 -R 1 ) ) ) | 
						
							| 41 | 9 40 | mtoi |  |-  ( _i e. RR -> -. _i < 0 ) | 
						
							| 42 |  | 0ne1 |  |-  0 =/= 1 | 
						
							| 43 | 42 | neii |  |-  -. 0 = 1 | 
						
							| 44 |  | oveq12 |  |-  ( ( _i = 0 /\ _i = 0 ) -> ( _i x. _i ) = ( 0 x. 0 ) ) | 
						
							| 45 | 44 | anidms |  |-  ( _i = 0 -> ( _i x. _i ) = ( 0 x. 0 ) ) | 
						
							| 46 | 45 | oveq1d |  |-  ( _i = 0 -> ( ( _i x. _i ) + 1 ) = ( ( 0 x. 0 ) + 1 ) ) | 
						
							| 47 |  | ax-i2m1 |  |-  ( ( _i x. _i ) + 1 ) = 0 | 
						
							| 48 |  | remul02 |  |-  ( 0 e. RR -> ( 0 x. 0 ) = 0 ) | 
						
							| 49 | 1 48 | ax-mp |  |-  ( 0 x. 0 ) = 0 | 
						
							| 50 | 49 | oveq1i |  |-  ( ( 0 x. 0 ) + 1 ) = ( 0 + 1 ) | 
						
							| 51 |  | readdlid |  |-  ( 1 e. RR -> ( 0 + 1 ) = 1 ) | 
						
							| 52 | 5 51 | ax-mp |  |-  ( 0 + 1 ) = 1 | 
						
							| 53 | 50 52 | eqtri |  |-  ( ( 0 x. 0 ) + 1 ) = 1 | 
						
							| 54 | 46 47 53 | 3eqtr3g |  |-  ( _i = 0 -> 0 = 1 ) | 
						
							| 55 | 43 54 | mto |  |-  -. _i = 0 | 
						
							| 56 | 55 | a1i |  |-  ( _i e. RR -> -. _i = 0 ) | 
						
							| 57 |  | mulgt0 |  |-  ( ( ( _i e. RR /\ 0 < _i ) /\ ( _i e. RR /\ 0 < _i ) ) -> 0 < ( _i x. _i ) ) | 
						
							| 58 | 57 | anidms |  |-  ( ( _i e. RR /\ 0 < _i ) -> 0 < ( _i x. _i ) ) | 
						
							| 59 |  | reixi |  |-  ( _i x. _i ) = ( 0 -R 1 ) | 
						
							| 60 | 58 59 | breqtrdi |  |-  ( ( _i e. RR /\ 0 < _i ) -> 0 < ( 0 -R 1 ) ) | 
						
							| 61 | 60 | ex |  |-  ( _i e. RR -> ( 0 < _i -> 0 < ( 0 -R 1 ) ) ) | 
						
							| 62 | 9 61 | mtoi |  |-  ( _i e. RR -> -. 0 < _i ) | 
						
							| 63 |  | 3ioran |  |-  ( -. ( _i < 0 \/ _i = 0 \/ 0 < _i ) <-> ( -. _i < 0 /\ -. _i = 0 /\ -. 0 < _i ) ) | 
						
							| 64 | 41 56 62 63 | syl3anbrc |  |-  ( _i e. RR -> -. ( _i < 0 \/ _i = 0 \/ 0 < _i ) ) | 
						
							| 65 | 3 64 | pm2.65i |  |-  -. _i e. RR |