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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 23956 | . . . 4 ⊢ (Poly‘𝑆) ⊆ (Poly‘ℂ) | |
2 | 1 | sseli 3599 | . . 3 ⊢ (𝐹 ∈ (Poly‘𝑆) → 𝐹 ∈ (Poly‘ℂ)) |
3 | ssid 3624 | . . . . 5 ⊢ ℂ ⊆ ℂ | |
4 | neg1cn 11124 | . . . . 5 ⊢ -1 ∈ ℂ | |
5 | plyconst 23962 | . . . . 5 ⊢ ((ℂ ⊆ ℂ ∧ -1 ∈ ℂ) → (ℂ × {-1}) ∈ (Poly‘ℂ)) | |
6 | 3, 4, 5 | mp2an 708 | . . . 4 ⊢ (ℂ × {-1}) ∈ (Poly‘ℂ) |
7 | 1 | sseli 3599 | . . . 4 ⊢ (𝐺 ∈ (Poly‘𝑆) → 𝐺 ∈ (Poly‘ℂ)) |
8 | plymulcl 23977 | . . . 4 ⊢ (((ℂ × {-1}) ∈ (Poly‘ℂ) ∧ 𝐺 ∈ (Poly‘ℂ)) → ((ℂ × {-1}) ∘𝑓 · 𝐺) ∈ (Poly‘ℂ)) | |
9 | 6, 7, 8 | sylancr 695 | . . 3 ⊢ (𝐺 ∈ (Poly‘𝑆) → ((ℂ × {-1}) ∘𝑓 · 𝐺) ∈ (Poly‘ℂ)) |
10 | dgrsub.1 | . . . 4 ⊢ 𝑀 = (deg‘𝐹) | |
11 | eqid 2622 | . . . 4 ⊢ (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) | |
12 | 10, 11 | dgradd 24023 | . . 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 494 | . 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 23954 | . . . 4 ⊢ (𝐹 ∈ (Poly‘𝑆) → 𝐹:ℂ⟶ℂ) | |
15 | plyf 23954 | . . . 4 ⊢ (𝐺 ∈ (Poly‘𝑆) → 𝐺:ℂ⟶ℂ) | |
16 | cnex 10017 | . . . . 5 ⊢ ℂ ∈ V | |
17 | ofnegsub 11018 | . . . . 5 ⊢ ((ℂ ∈ V ∧ 𝐹:ℂ⟶ℂ ∧ 𝐺:ℂ⟶ℂ) → (𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺)) = (𝐹 ∘𝑓 − 𝐺)) | |
18 | 16, 17 | mp3an1 1411 | . . . 4 ⊢ ((𝐹:ℂ⟶ℂ ∧ 𝐺:ℂ⟶ℂ) → (𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺)) = (𝐹 ∘𝑓 − 𝐺)) |
19 | 14, 15, 18 | syl2an 494 | . . 3 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺)) = (𝐹 ∘𝑓 − 𝐺)) |
20 | 19 | fveq2d 6195 | . 2 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘(𝐹 ∘𝑓 + ((ℂ × {-1}) ∘𝑓 · 𝐺))) = (deg‘(𝐹 ∘𝑓 − 𝐺))) |
21 | neg1ne0 11126 | . . . . . . 7 ⊢ -1 ≠ 0 | |
22 | dgrmulc 24027 | . . . . . . 7 ⊢ ((-1 ∈ ℂ ∧ -1 ≠ 0 ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = (deg‘𝐺)) | |
23 | 4, 21, 22 | mp3an12 1414 | . . . . . 6 ⊢ (𝐺 ∈ (Poly‘𝑆) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = (deg‘𝐺)) |
24 | dgrsub.2 | . . . . . 6 ⊢ 𝑁 = (deg‘𝐺) | |
25 | 23, 24 | syl6eqr 2674 | . . . . 5 ⊢ (𝐺 ∈ (Poly‘𝑆) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = 𝑁) |
26 | 25 | adantl 482 | . . . 4 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) = 𝑁) |
27 | 26 | breq2d 4665 | . . 3 ⊢ ((𝐹 ∈ (Poly‘𝑆) ∧ 𝐺 ∈ (Poly‘𝑆)) → (𝑀 ≤ (deg‘((ℂ × {-1}) ∘𝑓 · 𝐺)) ↔ 𝑀 ≤ 𝑁)) |
28 | 27, 26 | ifbieq1d 4109 | . 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 4684 | 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 384 = wceq 1483 ∈ wcel 1990 ≠ wne 2794 Vcvv 3200 ⊆ wss 3574 ifcif 4086 {csn 4177 class class class wbr 4653 × cxp 5112 ⟶wf 5884 ‘cfv 5888 (class class class)co 6650 ∘𝑓 cof 6895 ℂcc 9934 0cc0 9936 1c1 9937 + caddc 9939 · cmul 9941 ≤ cle 10075 − cmin 10266 -cneg 10267 Polycply 23940 degcdgr 23943 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-rep 4771 ax-sep 4781 ax-nul 4789 ax-pow 4843 ax-pr 4906 ax-un 6949 ax-inf2 8538 ax-cnex 9992 ax-resscn 9993 ax-1cn 9994 ax-icn 9995 ax-addcl 9996 ax-addrcl 9997 ax-mulcl 9998 ax-mulrcl 9999 ax-mulcom 10000 ax-addass 10001 ax-mulass 10002 ax-distr 10003 ax-i2m1 10004 ax-1ne0 10005 ax-1rid 10006 ax-rnegex 10007 ax-rrecex 10008 ax-cnre 10009 ax-pre-lttri 10010 ax-pre-lttrn 10011 ax-pre-ltadd 10012 ax-pre-mulgt0 10013 ax-pre-sup 10014 ax-addf 10015 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 df-3an 1039 df-tru 1486 df-fal 1489 df-ex 1705 df-nf 1710 df-sb 1881 df-eu 2474 df-mo 2475 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-nel 2898 df-ral 2917 df-rex 2918 df-reu 2919 df-rmo 2920 df-rab 2921 df-v 3202 df-sbc 3436 df-csb 3534 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-int 4476 df-iun 4522 df-br 4654 df-opab 4713 df-mpt 4730 df-tr 4753 df-id 5024 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-se 5074 df-we 5075 df-xp 5120 df-rel 5121 df-cnv 5122 df-co 5123 df-dm 5124 df-rn 5125 df-res 5126 df-ima 5127 df-pred 5680 df-ord 5726 df-on 5727 df-lim 5728 df-suc 5729 df-iota 5851 df-fun 5890 df-fn 5891 df-f 5892 df-f1 5893 df-fo 5894 df-f1o 5895 df-fv 5896 df-isom 5897 df-riota 6611 df-ov 6653 df-oprab 6654 df-mpt2 6655 df-of 6897 df-om 7066 df-1st 7168 df-2nd 7169 df-wrecs 7407 df-recs 7468 df-rdg 7506 df-1o 7560 df-oadd 7564 df-er 7742 df-map 7859 df-pm 7860 df-en 7956 df-dom 7957 df-sdom 7958 df-fin 7959 df-sup 8348 df-inf 8349 df-oi 8415 df-card 8765 df-pnf 10076 df-mnf 10077 df-xr 10078 df-ltxr 10079 df-le 10080 df-sub 10268 df-neg 10269 df-div 10685 df-nn 11021 df-2 11079 df-3 11080 df-n0 11293 df-z 11378 df-uz 11688 df-rp 11833 df-fz 12327 df-fzo 12466 df-fl 12593 df-seq 12802 df-exp 12861 df-hash 13118 df-cj 13839 df-re 13840 df-im 13841 df-sqrt 13975 df-abs 13976 df-clim 14219 df-rlim 14220 df-sum 14417 df-0p 23437 df-ply 23944 df-coe 23946 df-dgr 23947 |
This theorem is referenced by: dgrcolem2 24030 plydivlem4 24051 plydiveu 24053 dgrsub2 37705 |
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