Metamath Proof Explorer


Theorem mdegaddle

Description: The degree of a sum is at most the maximum of the degrees of the factors. (Contributed by Stefan O'Rear, 26-Mar-2015)

Ref Expression
Hypotheses mdegaddle.y ⊢ Y = I mPoly R
mdegaddle.d ⊢ D = I mDeg R
mdegaddle.i ⊢ φ → I ∈ V
mdegaddle.r ⊢ φ → R ∈ Ring
mdegaddle.b ⊢ B = Base Y
mdegaddle.p ⊢ + ˙ = + Y
mdegaddle.f ⊢ φ → F ∈ B
mdegaddle.g ⊢ φ → G ∈ B
Assertion mdegaddle ⊢ φ → D ⁡ F + ˙ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F

Proof

Step Hyp Ref Expression
1 mdegaddle.y ⊢ Y = I mPoly R
2 mdegaddle.d ⊢ D = I mDeg R
3 mdegaddle.i ⊢ φ → I ∈ V
4 mdegaddle.r ⊢ φ → R ∈ Ring
5 mdegaddle.b ⊢ B = Base Y
6 mdegaddle.p ⊢ + ˙ = + Y
7 mdegaddle.f ⊢ φ → F ∈ B
8 mdegaddle.g ⊢ φ → G ∈ B
9 eqid ⊢ + R = + R
10 1 5 9 6 7 8 mpladd ⊢ φ → F + ˙ G = F + R f G
11 10 fveq1d ⊢ φ → F + ˙ G ⁡ c = F + R f G ⁡ c
12 11 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → F + ˙ G ⁡ c = F + R f G ⁡ c
13 eqid ⊢ Base R = Base R
14 eqid ⊢ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin = a ∈ ℕ 0 I | a -1 ℕ ∈ Fin
15 1 13 5 14 7 mplelf ⊢ φ → F : a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟶ Base R
16 15 ffnd ⊢ φ → F Fn a ∈ ℕ 0 I | a -1 ℕ ∈ Fin
17 16 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → F Fn a ∈ ℕ 0 I | a -1 ℕ ∈ Fin
18 1 13 5 14 8 mplelf ⊢ φ → G : a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟶ Base R
19 18 ffnd ⊢ φ → G Fn a ∈ ℕ 0 I | a -1 ℕ ∈ Fin
20 19 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → G Fn a ∈ ℕ 0 I | a -1 ℕ ∈ Fin
21 ovex ⊢ ℕ 0 I ∈ V
22 21 rabex ⊢ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∈ V
23 22 a1i ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∈ V
24 simpr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin
25 fnfvof ⊢ F Fn a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ G Fn a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∈ V ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → F + R f G ⁡ c = F ⁡ c + R G ⁡ c
26 17 20 23 24 25 syl22anc ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → F + R f G ⁡ c = F ⁡ c + R G ⁡ c
27 12 26 eqtrd ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → F + ˙ G ⁡ c = F ⁡ c + R G ⁡ c
28 27 adantrr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F + ˙ G ⁡ c = F ⁡ c + R G ⁡ c
29 eqid ⊢ 0 R = 0 R
30 eqid ⊢ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b = b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b
31 7 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F ∈ B
32 simprl ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin
33 2 1 5 mdegxrcl ⊢ F ∈ B → D ⁡ F ∈ ℝ *
34 7 33 syl ⊢ φ → D ⁡ F ∈ ℝ *
35 34 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → D ⁡ F ∈ ℝ *
36 2 1 5 mdegxrcl ⊢ G ∈ B → D ⁡ G ∈ ℝ *
37 8 36 syl ⊢ φ → D ⁡ G ∈ ℝ *
38 37 34 ifcld ⊢ φ → if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ *
39 38 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ *
40 nn0ssre ⊢ ℕ 0 ⊆ ℝ
41 ressxr ⊢ ℝ ⊆ ℝ *
42 40 41 sstri ⊢ ℕ 0 ⊆ ℝ *
43 14 30 tdeglem1 ⊢ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b : a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟶ ℕ 0
44 43 a1i ⊢ φ → b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b : a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟶ ℕ 0
45 44 ffvelcdmda ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℕ 0
46 42 45 sselid ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℝ *
47 35 39 46 3jca ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → D ⁡ F ∈ ℝ * ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ * ∧ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℝ *
48 47 adantrr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ F ∈ ℝ * ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ * ∧ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℝ *
49 xrmax1 ⊢ D ⁡ F ∈ ℝ * ∧ D ⁡ G ∈ ℝ * → D ⁡ F ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F
50 34 37 49 syl2anc ⊢ φ → D ⁡ F ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F
51 50 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ F ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F
52 simprr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c
53 51 52 jca ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ F ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c
54 xrlelttr ⊢ D ⁡ F ∈ ℝ * ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ * ∧ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℝ * → D ⁡ F ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c
55 48 53 54 sylc ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c
56 2 1 5 29 14 30 31 32 55 mdeglt ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F ⁡ c = 0 R
57 8 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → G ∈ B
58 37 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → D ⁡ G ∈ ℝ *
59 58 39 46 3jca ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → D ⁡ G ∈ ℝ * ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ * ∧ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℝ *
60 59 adantrr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ G ∈ ℝ * ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ * ∧ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℝ *
61 xrmax2 ⊢ D ⁡ F ∈ ℝ * ∧ D ⁡ G ∈ ℝ * → D ⁡ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F
62 34 37 61 syl2anc ⊢ φ → D ⁡ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F
63 62 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F
64 63 52 jca ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c
65 xrlelttr ⊢ D ⁡ G ∈ ℝ * ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ * ∧ b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c ∈ ℝ * → D ⁡ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ G < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c
66 60 64 65 sylc ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → D ⁡ G < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c
67 2 1 5 29 14 30 57 32 66 mdeglt ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → G ⁡ c = 0 R
68 56 67 oveq12d ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F ⁡ c + R G ⁡ c = 0 R + R 0 R
69 ringgrp ⊢ R ∈ Ring → R ∈ Grp
70 4 69 syl ⊢ φ → R ∈ Grp
71 13 29 ring0cl ⊢ R ∈ Ring → 0 R ∈ Base R
72 4 71 syl ⊢ φ → 0 R ∈ Base R
73 13 9 29 grplid ⊢ R ∈ Grp ∧ 0 R ∈ Base R → 0 R + R 0 R = 0 R
74 70 72 73 syl2anc ⊢ φ → 0 R + R 0 R = 0 R
75 74 adantr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → 0 R + R 0 R = 0 R
76 68 75 eqtrd ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F ⁡ c + R G ⁡ c = 0 R
77 28 76 eqtrd ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F + ˙ G ⁡ c = 0 R
78 77 expr ⊢ φ ∧ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin → if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F + ˙ G ⁡ c = 0 R
79 78 ralrimiva ⊢ φ → ∀ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F + ˙ G ⁡ c = 0 R
80 1 3 4 mplringd ⊢ φ → Y ∈ Ring
81 5 6 ringacl ⊢ Y ∈ Ring ∧ F ∈ B ∧ G ∈ B → F + ˙ G ∈ B
82 80 7 8 81 syl3anc ⊢ φ → F + ˙ G ∈ B
83 2 1 5 29 14 30 mdegleb ⊢ F + ˙ G ∈ B ∧ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ∈ ℝ * → D ⁡ F + ˙ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ↔ ∀ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F + ˙ G ⁡ c = 0 R
84 82 38 83 syl2anc ⊢ φ → D ⁡ F + ˙ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F ↔ ∀ c ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F < b ∈ a ∈ ℕ 0 I | a -1 ℕ ∈ Fin ⟼ ∑ ℂ fld b ⁡ c → F + ˙ G ⁡ c = 0 R
85 79 84 mpbird ⊢ φ → D ⁡ F + ˙ G ≤ if D ⁡ F ≤ D ⁡ G D ⁡ G D ⁡ F