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Mirrors > Home > MPE Home > Th. List > dgrsub | Structured version Visualization version GIF version |
Description: The degree of a difference of polynomials is at most the maximum of the degrees. (Contributed by Mario Carneiro, 26-Jul-2014.) |
Ref | Expression |
---|---|
dgrsub.1 | ⊢ 𝑀 = (deg‘𝐹) |
dgrsub.2 | ⊢ 𝑁 = (deg‘𝐺) |
Ref | Expression |
---|---|
dgrsub | ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘(𝐹 ∘𝑓 − 𝐺)) ≤ if(𝑀 ≤ 𝑁, 𝑁, 𝑀)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | plyssc 24176 | . . . 4 ⊢ (Poly‘𝑆) ⊆ (Poly‘ℂ) | |
2 | 1 | sseli 3748 | . . 3 ⊢ (𝐹 ∈ (Poly‘𝑆) → 𝐹 ∈ (Poly‘ℂ)) |
3 | ssid 3773 | . . . . 5 ⊢ ℂ ⊆ ℂ | |
4 | neg1cn 11326 | . . . . 5 ⊢ -1 ∈ ℂ | |
5 | plyconst 24182 | . . . . 5 ⊢ ((ℂ ⊆ ℂ ∧ -1 ∈ ℂ) → (ℂ × {-1}) ∈ (Poly‘ℂ)) | |
6 | 3, 4, 5 | mp2an 672 | . . . 4 ⊢ (ℂ × {-1}) ∈ (Poly‘ℂ) |
7 | 1 | sseli 3748 | . . . 4 ⊢ (𝐺 ∈ (Poly‘𝑆) → 𝐺 ∈ (Poly‘ℂ)) |
8 | plymulcl 24197 | . . . 4 ⊢ (((ℂ × {-1}) ∈ (Poly‘ℂ) ∧ 𝐺 ∈ (Poly‘ℂ)) → ((ℂ × {-1}) ∘𝑓 · 𝐺) ∈ (Poly‘ℂ)) | |
9 | 6, 7, 8 | sylancr 575 | . . 3 ⊢ (𝐺 ∈ (Poly‘𝑆) → ((ℂ × {-1}) ∘𝑓 · 𝐺) ∈ (Poly‘ℂ)) |
10 | dgrsub.1 | . . . 4 ⊢ 𝑀 = (deg‘𝐹) | |
11 | eqid 2771 | . . . 4 ⊢ (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) | |
12 | 10, 11 | dgradd 24243 | . . 3 ⊢ ((𝐹 ∈ (Poly‘ℂ) ∧ ((ℂ × {-1}) ∘𝑓 · 𝐺) ∈ (Poly‘ℂ)) → (deg‘(𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺))) ≤ if(𝑀 ≤ (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)), (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)), 𝑀)) |
13 | 2, 9, 12 | syl2an 583 | . 2 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘(𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺))) ≤ if(𝑀 ≤ (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)), (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)), 𝑀)) |
14 | plyf 24174 | . . . 4 ⊢ (𝐹 ∈ (Poly‘𝑆) → 𝐹:ℂ⟶ℂ) | |
15 | plyf 24174 | . . . 4 ⊢ (𝐺 ∈ (Poly‘𝑆) → 𝐺:ℂ⟶ℂ) | |
16 | cnex 10219 | . . . . 5 ⊢ ℂ ∈ V | |
17 | ofnegsub 11220 | . . . . 5 ⊢ ((ℂ ∈ V ∧ 𝐹:ℂ⟶ℂ ∧ 𝐺:ℂ⟶ℂ) → (𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺)) = (𝐹 ∘𝑓 − 𝐺)) | |
18 | 16, 17 | mp3an1 1559 | . . . 4 ⊢ ((𝐹:ℂ⟶ℂ ∧ 𝐺:ℂ⟶ℂ) → (𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺)) = (𝐹 ∘𝑓 − 𝐺)) |
19 | 14, 15, 18 | syl2an 583 | . . 3 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺)) = (𝐹 ∘𝑓 − 𝐺)) |
20 | 19 | fveq2d 6336 | . 2 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘(𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺))) = (deg‘(𝐹 ∘𝑓 − 𝐺))) |
21 | neg1ne0 11328 | . . . . . . 7 ⊢ -1 ≠ 0 | |
22 | dgrmulc 24247 | . . . . . . 7 ⊢ ((-1 ∈ ℂ ∧ -1 ≠ 0 ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = (deg‘𝐺)) | |
23 | 4, 21, 22 | mp3an12 1562 | . . . . . 6 ⊢ (𝐺 ∈ (Poly‘𝑆) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = (deg‘𝐺)) |
24 | dgrsub.2 | . . . . . 6 ⊢ 𝑁 = (deg‘𝐺) | |
25 | 23, 24 | syl6eqr 2823 | . . . . 5 ⊢ (𝐺 ∈ (Poly‘𝑆) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = 𝑁) |
26 | 25 | adantl 467 | . . . 4 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = 𝑁) |
27 | 26 | breq2d 4798 | . . 3 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (𝑀 ≤ (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) ↔ 𝑀 ≤ 𝑁)) |
28 | 27, 26 | ifbieq1d 4248 | . 2 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → if(𝑀 ≤ (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)), (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)), 𝑀) = if(𝑀 ≤ 𝑁, 𝑁, 𝑀)) |
29 | 13, 20, 28 | 3brtr3d 4817 | 1 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘(𝐹 ∘𝑓 − 𝐺)) ≤ if(𝑀 ≤ 𝑁, 𝑁, 𝑀)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 382 = wceq 1631 ∈ wcel 2145 ≠ wne 2943 Vcvv 3351 ⊆ wss 3723 ifcif 4225 {csn 4316 class class class wbr 4786 × cxp 5247 ⟶wf 6027 ‘cfv 6031 (class class class)co 6793 ∘𝑓 cof 7042 ℂcc 10136 0cc0 10138 1c1 10139 + caddc 10141 · cmul 10143 ≤ cle 10277 − cmin 10468 -cneg 10469 Polycply 24160 degcdgr 24163 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1870 ax-4 1885 ax-5 1991 ax-6 2057 ax-7 2093 ax-8 2147 ax-9 2154 ax-10 2174 ax-11 2190 ax-12 2203 ax-13 2408 ax-ext 2751 ax-rep 4904 ax-sep 4915 ax-nul 4923 ax-pow 4974 ax-pr 5034 ax-un 7096 ax-inf2 8702 ax-cnex 10194 ax-resscn 10195 ax-1cn 10196 ax-icn 10197 ax-addcl 10198 ax-addrcl 10199 ax-mulcl 10200 ax-mulrcl 10201 ax-mulcom 10202 ax-addass 10203 ax-mulass 10204 ax-distr 10205 ax-i2m1 10206 ax-1ne0 10207 ax-1rid 10208 ax-rnegex 10209 ax-rrecex 10210 ax-cnre 10211 ax-pre-lttri 10212 ax-pre-lttrn 10213 ax-pre-ltadd 10214 ax-pre-mulgt0 10215 ax-pre-sup 10216 ax-addf 10217 |
This theorem depends on definitions: df-bi 197 df-an 383 df-or 835 df-3or 1072 df-3an 1073 df-tru 1634 df-fal 1637 df-ex 1853 df-nf 1858 df-sb 2050 df-eu 2622 df-mo 2623 df-clab 2758 df-cleq 2764 df-clel 2767 df-nfc 2902 df-ne 2944 df-nel 3047 df-ral 3066 df-rex 3067 df-reu 3068 df-rmo 3069 df-rab 3070 df-v 3353 df-sbc 3588 df-csb 3683 df-dif 3726 df-un 3728 df-in 3730 df-ss 3737 df-pss 3739 df-nul 4064 df-if 4226 df-pw 4299 df-sn 4317 df-pr 4319 df-tp 4321 df-op 4323 df-uni 4575 df-int 4612 df-iun 4656 df-br 4787 df-opab 4847 df-mpt 4864 df-tr 4887 df-id 5157 df-eprel 5162 df-po 5170 df-so 5171 df-fr 5208 df-se 5209 df-we 5210 df-xp 5255 df-rel 5256 df-cnv 5257 df-co 5258 df-dm 5259 df-rn 5260 df-res 5261 df-ima 5262 df-pred 5823 df-ord 5869 df-on 5870 df-lim 5871 df-suc 5872 df-iota 5994 df-fun 6033 df-fn 6034 df-f 6035 df-f1 6036 df-fo 6037 df-f1o 6038 df-fv 6039 df-isom 6040 df-riota 6754 df-ov 6796 df-oprab 6797 df-mpt2 6798 df-of 7044 df-om 7213 df-1st 7315 df-2nd 7316 df-wrecs 7559 df-recs 7621 df-rdg 7659 df-1o 7713 df-oadd 7717 df-er 7896 df-map 8011 df-pm 8012 df-en 8110 df-dom 8111 df-sdom 8112 df-fin 8113 df-sup 8504 df-inf 8505 df-oi 8571 df-card 8965 df-pnf 10278 df-mnf 10279 df-xr 10280 df-ltxr 10281 df-le 10282 df-sub 10470 df-neg 10471 df-div 10887 df-nn 11223 df-2 11281 df-3 11282 df-n0 11495 df-z 11580 df-uz 11889 df-rp 12036 df-fz 12534 df-fzo 12674 df-fl 12801 df-seq 13009 df-exp 13068 df-hash 13322 df-cj 14047 df-re 14048 df-im 14049 df-sqrt 14183 df-abs 14184 df-clim 14427 df-rlim 14428 df-sum 14625 df-0p 23657 df-ply 24164 df-coe 24166 df-dgr 24167 |
This theorem is referenced by: dgrcolem2 24250 plydivlem4 24271 plydiveu 24273 dgrsub2 38231 |
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