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Description: A proof of 1ne2 without using ax-mulcom , ax-mulass , ax-pre-mulgt0 . Based on mul02lem2 . (Contributed by SN, 13-Dec-2023)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | sn-1ne2 | |- 1 =/= 2 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0ne1 | |- 0 =/= 1 |
|
| 2 | ax-icn | |- _i e. CC |
|
| 3 | 2 2 | mulcli | |- ( _i x. _i ) e. CC |
| 4 | ax-1cn | |- 1 e. CC |
|
| 5 | 3 4 4 | addassi | |- ( ( ( _i x. _i ) + 1 ) + 1 ) = ( ( _i x. _i ) + ( 1 + 1 ) ) |
| 6 | 5 | a1i | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> ( ( ( _i x. _i ) + 1 ) + 1 ) = ( ( _i x. _i ) + ( 1 + 1 ) ) ) |
| 7 | simpr | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> 1 = ( 1 + 1 ) ) |
|
| 8 | 7 | oveq2d | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> ( ( _i x. _i ) + 1 ) = ( ( _i x. _i ) + ( 1 + 1 ) ) ) |
| 9 | ax-i2m1 | |- ( ( _i x. _i ) + 1 ) = 0 |
|
| 10 | 9 | a1i | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> ( ( _i x. _i ) + 1 ) = 0 ) |
| 11 | 6 8 10 | 3eqtr2rd | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> 0 = ( ( ( _i x. _i ) + 1 ) + 1 ) ) |
| 12 | simpl | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> 0 = ( 0 + 0 ) ) |
|
| 13 | 10 | oveq1d | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> ( ( ( _i x. _i ) + 1 ) + 1 ) = ( 0 + 1 ) ) |
| 14 | 11 12 13 | 3eqtr3d | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> ( 0 + 0 ) = ( 0 + 1 ) ) |
| 15 | 0red | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> 0 e. RR ) |
|
| 16 | 1red | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> 1 e. RR ) |
|
| 17 | readdcan | |- ( ( 0 e. RR /\ 1 e. RR /\ 0 e. RR ) -> ( ( 0 + 0 ) = ( 0 + 1 ) <-> 0 = 1 ) ) |
|
| 18 | 15 16 15 17 | syl3anc | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> ( ( 0 + 0 ) = ( 0 + 1 ) <-> 0 = 1 ) ) |
| 19 | 14 18 | mpbid | |- ( ( 0 = ( 0 + 0 ) /\ 1 = ( 1 + 1 ) ) -> 0 = 1 ) |
| 20 | 19 | ex | |- ( 0 = ( 0 + 0 ) -> ( 1 = ( 1 + 1 ) -> 0 = 1 ) ) |
| 21 | 20 | necon3d | |- ( 0 = ( 0 + 0 ) -> ( 0 =/= 1 -> 1 =/= ( 1 + 1 ) ) ) |
| 22 | 1 21 | mpi | |- ( 0 = ( 0 + 0 ) -> 1 =/= ( 1 + 1 ) ) |
| 23 | oveq2 | |- ( 1 = ( 1 + 1 ) -> ( 0 x. 1 ) = ( 0 x. ( 1 + 1 ) ) ) |
|
| 24 | 0re | |- 0 e. RR |
|
| 25 | ax-1rid | |- ( 0 e. RR -> ( 0 x. 1 ) = 0 ) |
|
| 26 | 24 25 | ax-mp | |- ( 0 x. 1 ) = 0 |
| 27 | 0cn | |- 0 e. CC |
|
| 28 | 27 4 4 | adddii | |- ( 0 x. ( 1 + 1 ) ) = ( ( 0 x. 1 ) + ( 0 x. 1 ) ) |
| 29 | 26 26 | oveq12i | |- ( ( 0 x. 1 ) + ( 0 x. 1 ) ) = ( 0 + 0 ) |
| 30 | 28 29 | eqtri | |- ( 0 x. ( 1 + 1 ) ) = ( 0 + 0 ) |
| 31 | 23 26 30 | 3eqtr3g | |- ( 1 = ( 1 + 1 ) -> 0 = ( 0 + 0 ) ) |
| 32 | 31 | necon3i | |- ( 0 =/= ( 0 + 0 ) -> 1 =/= ( 1 + 1 ) ) |
| 33 | 22 32 | pm2.61ine | |- 1 =/= ( 1 + 1 ) |
| 34 | df-2 | |- 2 = ( 1 + 1 ) |
|
| 35 | 33 34 | neeqtrri | |- 1 =/= 2 |