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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 24797 | . . . 4 ⊢ (Poly‘𝑆) ⊆ (Poly‘ℂ) | |
2 | 1 | sseli 3911 | . . 3 ⊢ (𝐹 ∈ (Poly‘𝑆) → 𝐹 ∈ (Poly‘ℂ)) |
3 | ssid 3937 | . . . . 5 ⊢ ℂ ⊆ ℂ | |
4 | neg1cn 11739 | . . . . 5 ⊢ -1 ∈ ℂ | |
5 | plyconst 24803 | . . . . 5 ⊢ ((ℂ ⊆ ℂ ∧ -1 ∈ ℂ) → (ℂ × {-1}) ∈ (Poly‘ℂ)) | |
6 | 3, 4, 5 | mp2an 691 | . . . 4 ⊢ (ℂ × {-1}) ∈ (Poly‘ℂ) |
7 | 1 | sseli 3911 | . . . 4 ⊢ (𝐺 ∈ (Poly‘𝑆) → 𝐺 ∈ (Poly‘ℂ)) |
8 | plymulcl 24818 | . . . 4 ⊢ (((ℂ × {-1}) ∈ (Poly‘ℂ) ∧ 𝐺 ∈ (Poly‘ℂ)) → ((ℂ × {-1}) ∘f · 𝐺) ∈ (Poly‘ℂ)) | |
9 | 6, 7, 8 | sylancr 590 | . . 3 ⊢ (𝐺 ∈ (Poly‘𝑆) → ((ℂ × {-1}) ∘f · 𝐺) ∈ (Poly‘ℂ)) |
10 | dgrsub.1 | . . . 4 ⊢ 𝑀 = (deg‘𝐹) | |
11 | eqid 2798 | . . . 4 ⊢ (deg‘((ℂ × {-1}) ∘f · 𝐺)) = (deg‘((ℂ × {-1}) ∘f · 𝐺)) | |
12 | 10, 11 | dgradd 24864 | . . 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 598 | . 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 | cnex 10607 | . . . 4 ⊢ ℂ ∈ V | |
15 | plyf 24795 | . . . 4 ⊢ (𝐹 ∈ (Poly‘𝑆) → 𝐹:ℂ⟶ℂ) | |
16 | plyf 24795 | . . . 4 ⊢ (𝐺 ∈ (Poly‘𝑆) → 𝐺:ℂ⟶ℂ) | |
17 | ofnegsub 11623 | . . . 4 ⊢ ((ℂ ∈ V ∧ 𝐹:ℂ⟶ℂ ∧ 𝐺:ℂ⟶ℂ) → (𝐹 ∘f + ((ℂ × {-1}) ∘f · 𝐺)) = (𝐹 ∘f − 𝐺)) | |
18 | 14, 15, 16, 17 | mp3an3an 1464 | . . 3 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (𝐹 ∘f + ((ℂ × {-1}) ∘f · 𝐺)) = (𝐹 ∘f − 𝐺)) |
19 | 18 | fveq2d 6649 | . 2 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘(𝐹 ∘f + ((ℂ × {-1}) ∘f · 𝐺))) = (deg‘(𝐹 ∘f − 𝐺))) |
20 | neg1ne0 11741 | . . . . . . 7 ⊢ -1 ≠ 0 | |
21 | dgrmulc 24868 | . . . . . . 7 ⊢ ((-1 ∈ ℂ ∧ -1 ≠ 0 ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘((ℂ × {-1}) ∘f · 𝐺)) = (deg‘𝐺)) | |
22 | 4, 20, 21 | mp3an12 1448 | . . . . . 6 ⊢ (𝐺 ∈ (Poly‘𝑆) → (deg‘((ℂ × {-1}) ∘f · 𝐺)) = (deg‘𝐺)) |
23 | dgrsub.2 | . . . . . 6 ⊢ 𝑁 = (deg‘𝐺) | |
24 | 22, 23 | eqtr4di 2851 | . . . . 5 ⊢ (𝐺 ∈ (Poly‘𝑆) → (deg‘((ℂ × {-1}) ∘f · 𝐺)) = 𝑁) |
25 | 24 | adantl 485 | . . . 4 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘((ℂ × {-1}) ∘f · 𝐺)) = 𝑁) |
26 | 25 | breq2d 5042 | . . 3 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (𝑀 ≤ (deg‘((ℂ × {-1}) ∘f · 𝐺)) ↔ 𝑀 ≤ 𝑁)) |
27 | 26, 25 | ifbieq1d 4448 | . 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)) |
28 | 13, 19, 27 | 3brtr3d 5061 | 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 399 = wceq 1538 ∈ wcel 2111 ≠ wne 2987 Vcvv 3441 ⊆ wss 3881 ifcif 4425 {csn 4525 class class class wbr 5030 × cxp 5517 ⟶wf 6320 ‘cfv 6324 (class class class)co 7135 ∘f cof 7387 ℂcc 10524 0cc0 10526 1c1 10527 + caddc 10529 · cmul 10531 ≤ cle 10665 − cmin 10859 -cneg 10860 Polycply 24781 degcdgr 24784 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2113 ax-9 2121 ax-10 2142 ax-11 2158 ax-12 2175 ax-ext 2770 ax-rep 5154 ax-sep 5167 ax-nul 5174 ax-pow 5231 ax-pr 5295 ax-un 7441 ax-inf2 9088 ax-cnex 10582 ax-resscn 10583 ax-1cn 10584 ax-icn 10585 ax-addcl 10586 ax-addrcl 10587 ax-mulcl 10588 ax-mulrcl 10589 ax-mulcom 10590 ax-addass 10591 ax-mulass 10592 ax-distr 10593 ax-i2m1 10594 ax-1ne0 10595 ax-1rid 10596 ax-rnegex 10597 ax-rrecex 10598 ax-cnre 10599 ax-pre-lttri 10600 ax-pre-lttrn 10601 ax-pre-ltadd 10602 ax-pre-mulgt0 10603 ax-pre-sup 10604 ax-addf 10605 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 845 df-3or 1085 df-3an 1086 df-tru 1541 df-fal 1551 df-ex 1782 df-nf 1786 df-sb 2070 df-mo 2598 df-eu 2629 df-clab 2777 df-cleq 2791 df-clel 2870 df-nfc 2938 df-ne 2988 df-nel 3092 df-ral 3111 df-rex 3112 df-reu 3113 df-rmo 3114 df-rab 3115 df-v 3443 df-sbc 3721 df-csb 3829 df-dif 3884 df-un 3886 df-in 3888 df-ss 3898 df-pss 3900 df-nul 4244 df-if 4426 df-pw 4499 df-sn 4526 df-pr 4528 df-tp 4530 df-op 4532 df-uni 4801 df-int 4839 df-iun 4883 df-br 5031 df-opab 5093 df-mpt 5111 df-tr 5137 df-id 5425 df-eprel 5430 df-po 5438 df-so 5439 df-fr 5478 df-se 5479 df-we 5480 df-xp 5525 df-rel 5526 df-cnv 5527 df-co 5528 df-dm 5529 df-rn 5530 df-res 5531 df-ima 5532 df-pred 6116 df-ord 6162 df-on 6163 df-lim 6164 df-suc 6165 df-iota 6283 df-fun 6326 df-fn 6327 df-f 6328 df-f1 6329 df-fo 6330 df-f1o 6331 df-fv 6332 df-isom 6333 df-riota 7093 df-ov 7138 df-oprab 7139 df-mpo 7140 df-of 7389 df-om 7561 df-1st 7671 df-2nd 7672 df-wrecs 7930 df-recs 7991 df-rdg 8029 df-1o 8085 df-oadd 8089 df-er 8272 df-map 8391 df-pm 8392 df-en 8493 df-dom 8494 df-sdom 8495 df-fin 8496 df-sup 8890 df-inf 8891 df-oi 8958 df-card 9352 df-pnf 10666 df-mnf 10667 df-xr 10668 df-ltxr 10669 df-le 10670 df-sub 10861 df-neg 10862 df-div 11287 df-nn 11626 df-2 11688 df-3 11689 df-n0 11886 df-z 11970 df-uz 12232 df-rp 12378 df-fz 12886 df-fzo 13029 df-fl 13157 df-seq 13365 df-exp 13426 df-hash 13687 df-cj 14450 df-re 14451 df-im 14452 df-sqrt 14586 df-abs 14587 df-clim 14837 df-rlim 14838 df-sum 15035 df-0p 24274 df-ply 24785 df-coe 24787 df-dgr 24788 |
This theorem is referenced by: dgrcolem2 24871 plydivlem4 24892 plydiveu 24894 dgrsub2 40079 |
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