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Description: Lemma for divalg . (Contributed by Paul Chapman, 21-Mar-2011)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | divalglem0.1 | |- N e. ZZ |
|
| divalglem0.2 | |- D e. ZZ |
||
| divalglem1.3 | |- D =/= 0 |
||
| Assertion | divalglem1 | |- 0 <_ ( N + ( abs ` ( N x. D ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | divalglem0.1 | |- N e. ZZ |
|
| 2 | divalglem0.2 | |- D e. ZZ |
|
| 3 | divalglem1.3 | |- D =/= 0 |
|
| 4 | 1 | zrei | |- N e. RR |
| 5 | 0re | |- 0 e. RR |
|
| 6 | 4 5 | letrii | |- ( N <_ 0 \/ 0 <_ N ) |
| 7 | nnabscl | |- ( ( D e. ZZ /\ D =/= 0 ) -> ( abs ` D ) e. NN ) |
|
| 8 | 2 3 7 | mp2an | |- ( abs ` D ) e. NN |
| 9 | nnge1 | |- ( ( abs ` D ) e. NN -> 1 <_ ( abs ` D ) ) |
|
| 10 | 8 9 | ax-mp | |- 1 <_ ( abs ` D ) |
| 11 | le0neg1 | |- ( N e. RR -> ( N <_ 0 <-> 0 <_ -u N ) ) |
|
| 12 | 4 11 | ax-mp | |- ( N <_ 0 <-> 0 <_ -u N ) |
| 13 | 4 | renegcli | |- -u N e. RR |
| 14 | 2 | zrei | |- D e. RR |
| 15 | 14 | recni | |- D e. CC |
| 16 | 15 | abscli | |- ( abs ` D ) e. RR |
| 17 | lemulge11 | |- ( ( ( -u N e. RR /\ ( abs ` D ) e. RR ) /\ ( 0 <_ -u N /\ 1 <_ ( abs ` D ) ) ) -> -u N <_ ( -u N x. ( abs ` D ) ) ) |
|
| 18 | 13 16 17 | mpanl12 | |- ( ( 0 <_ -u N /\ 1 <_ ( abs ` D ) ) -> -u N <_ ( -u N x. ( abs ` D ) ) ) |
| 19 | 12 18 | sylanb | |- ( ( N <_ 0 /\ 1 <_ ( abs ` D ) ) -> -u N <_ ( -u N x. ( abs ` D ) ) ) |
| 20 | 10 19 | mpan2 | |- ( N <_ 0 -> -u N <_ ( -u N x. ( abs ` D ) ) ) |
| 21 | 4 | recni | |- N e. CC |
| 22 | 21 15 | absmuli | |- ( abs ` ( N x. D ) ) = ( ( abs ` N ) x. ( abs ` D ) ) |
| 23 | 4 | absnidi | |- ( N <_ 0 -> ( abs ` N ) = -u N ) |
| 24 | 23 | oveq1d | |- ( N <_ 0 -> ( ( abs ` N ) x. ( abs ` D ) ) = ( -u N x. ( abs ` D ) ) ) |
| 25 | 22 24 | eqtrid | |- ( N <_ 0 -> ( abs ` ( N x. D ) ) = ( -u N x. ( abs ` D ) ) ) |
| 26 | 20 25 | breqtrrd | |- ( N <_ 0 -> -u N <_ ( abs ` ( N x. D ) ) ) |
| 27 | le0neg2 | |- ( N e. RR -> ( 0 <_ N <-> -u N <_ 0 ) ) |
|
| 28 | 4 27 | ax-mp | |- ( 0 <_ N <-> -u N <_ 0 ) |
| 29 | 4 14 | remulcli | |- ( N x. D ) e. RR |
| 30 | 29 | recni | |- ( N x. D ) e. CC |
| 31 | 30 | absge0i | |- 0 <_ ( abs ` ( N x. D ) ) |
| 32 | 30 | abscli | |- ( abs ` ( N x. D ) ) e. RR |
| 33 | 13 5 32 | letri | |- ( ( -u N <_ 0 /\ 0 <_ ( abs ` ( N x. D ) ) ) -> -u N <_ ( abs ` ( N x. D ) ) ) |
| 34 | 31 33 | mpan2 | |- ( -u N <_ 0 -> -u N <_ ( abs ` ( N x. D ) ) ) |
| 35 | 28 34 | sylbi | |- ( 0 <_ N -> -u N <_ ( abs ` ( N x. D ) ) ) |
| 36 | 26 35 | jaoi | |- ( ( N <_ 0 \/ 0 <_ N ) -> -u N <_ ( abs ` ( N x. D ) ) ) |
| 37 | 6 36 | ax-mp | |- -u N <_ ( abs ` ( N x. D ) ) |
| 38 | df-neg | |- -u N = ( 0 - N ) |
|
| 39 | 38 | breq1i | |- ( -u N <_ ( abs ` ( N x. D ) ) <-> ( 0 - N ) <_ ( abs ` ( N x. D ) ) ) |
| 40 | 5 4 32 | lesubadd2i | |- ( ( 0 - N ) <_ ( abs ` ( N x. D ) ) <-> 0 <_ ( N + ( abs ` ( N x. D ) ) ) ) |
| 41 | 39 40 | bitri | |- ( -u N <_ ( abs ` ( N x. D ) ) <-> 0 <_ ( N + ( abs ` ( N x. D ) ) ) ) |
| 42 | 37 41 | mpbi | |- 0 <_ ( N + ( abs ` ( N x. D ) ) ) |