Metamath Proof Explorer


Theorem rngunsnply1chr2

Description: When adjoining an element X with characteristic polynomial of degree 2 to a subring S , the elements Y of the generated subring can be written as a linear form. (Contributed by Thierry Arnoux, 8-Nov-2026)

Ref Expression
Hypotheses rngunsnply1chr2.v ⊢ V = Base R
rngunsnply1chr2.p ⊢ P = Poly 1 ⁡ R ↾ 𝑠 S
rngunsnply1chr2.u ⊢ U = Base P
rngunsnply1chr2.q ⊢ Q = R evalSub 1 S
rngunsnply1chr2.r ⊢ φ → R ∈ CRing
rngunsnply1chr2.1 ⊢ φ → R ∈ NzRing
rngunsnply1chr2.s ⊢ φ → S ∈ SubRing ⁡ R
rngunsnply1chr2.x ⊢ φ → X ∈ V
rngunsnply1chr2.y ⊢ φ → Y ∈ N ⁡ S ∪ X
rngunsnply1chr2.n ⊢ N = RingSpan ⁡ R
rngunsnply1chr2.2 ⊢ + ˙ = + R
rngunsnply1chr2.3 ⊢ · ˙ = ⋅ R
rngunsnply1chr2.4 ⊢ × ˙ = ⋅ mulGrp R
rngunsnply1chr2.a ⊢ φ → A ∈ S
rngunsnply1chr2.b ⊢ φ → B ∈ S
rngunsnply1chr2.5 ⊢ φ → 2 × ˙ X = A · ˙ X + ˙ B
Assertion rngunsnply1chr2 ⊢ φ → ∃ a ∈ S ∃ b ∈ S Y = a · ˙ X + ˙ b

Proof

Step Hyp Ref Expression
1 rngunsnply1chr2.v ⊢ V = Base R
2 rngunsnply1chr2.p ⊢ P = Poly 1 ⁡ R ↾ 𝑠 S
3 rngunsnply1chr2.u ⊢ U = Base P
4 rngunsnply1chr2.q ⊢ Q = R evalSub 1 S
5 rngunsnply1chr2.r ⊢ φ → R ∈ CRing
6 rngunsnply1chr2.1 ⊢ φ → R ∈ NzRing
7 rngunsnply1chr2.s ⊢ φ → S ∈ SubRing ⁡ R
8 rngunsnply1chr2.x ⊢ φ → X ∈ V
9 rngunsnply1chr2.y ⊢ φ → Y ∈ N ⁡ S ∪ X
10 rngunsnply1chr2.n ⊢ N = RingSpan ⁡ R
11 rngunsnply1chr2.2 ⊢ + ˙ = + R
12 rngunsnply1chr2.3 ⊢ · ˙ = ⋅ R
13 rngunsnply1chr2.4 ⊢ × ˙ = ⋅ mulGrp R
14 rngunsnply1chr2.a ⊢ φ → A ∈ S
15 rngunsnply1chr2.b ⊢ φ → B ∈ S
16 rngunsnply1chr2.5 ⊢ φ → 2 × ˙ X = A · ˙ X + ˙ B
17 oveq1 ⊢ a = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 → a · ˙ X = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X
18 17 oveq1d ⊢ a = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 → a · ˙ X + ˙ b = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ b
19 18 eqeq2d ⊢ a = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 → Y = a · ˙ X + ˙ b ↔ Y = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ b
20 oveq2 ⊢ b = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0 → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ b = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0
21 20 eqeq2d ⊢ b = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0 → Y = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ b ↔ Y = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0
22 eqid ⊢ R ↾ 𝑠 S = R ↾ 𝑠 S
23 22 subrgring ⊢ S ∈ SubRing ⁡ R → R ↾ 𝑠 S ∈ Ring
24 7 23 syl ⊢ φ → R ↾ 𝑠 S ∈ Ring
25 24 adantr ⊢ φ ∧ p ∈ U → R ↾ 𝑠 S ∈ Ring
26 simpr ⊢ φ ∧ p ∈ U → p ∈ U
27 5 adantr ⊢ φ ∧ p ∈ U → R ∈ CRing
28 6 adantr ⊢ φ ∧ p ∈ U → R ∈ NzRing
29 7 adantr ⊢ φ ∧ p ∈ U → S ∈ SubRing ⁡ R
30 8 adantr ⊢ φ ∧ p ∈ U → X ∈ V
31 9 adantr ⊢ φ ∧ p ∈ U → Y ∈ N ⁡ S ∪ X
32 14 adantr ⊢ φ ∧ p ∈ U → A ∈ S
33 15 adantr ⊢ φ ∧ p ∈ U → B ∈ S
34 16 adantr ⊢ φ ∧ p ∈ U → 2 × ˙ X = A · ˙ X + ˙ B
35 eqid ⊢ deg 1 ⁡ R = deg 1 ⁡ R
36 eqid ⊢ rem 1p ⁡ R ↾ 𝑠 S = rem 1p ⁡ R ↾ 𝑠 S
37 eqid ⊢ 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B = 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B
38 eqid ⊢ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B = p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B
39 1 2 3 4 27 28 29 30 31 10 11 12 13 32 33 34 35 36 37 38 26 rngunsnply1chr2lem2 ⊢ φ ∧ p ∈ U → 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ∈ Unic 1p ⁡ R ↾ 𝑠 S
40 eqid ⊢ Unic 1p ⁡ R ↾ 𝑠 S = Unic 1p ⁡ R ↾ 𝑠 S
41 36 2 3 40 r1pcl ⊢ R ↾ 𝑠 S ∈ Ring ∧ p ∈ U ∧ 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ∈ Unic 1p ⁡ R ↾ 𝑠 S → p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ∈ U
42 25 26 39 41 syl3anc ⊢ φ ∧ p ∈ U → p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ∈ U
43 1nn0 ⊢ 1 ∈ ℕ 0
44 eqid ⊢ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B
45 eqid ⊢ Base R ↾ 𝑠 S = Base R ↾ 𝑠 S
46 44 3 2 45 coe1fvalcl ⊢ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ∈ U ∧ 1 ∈ ℕ 0 → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 ∈ Base R ↾ 𝑠 S
47 42 43 46 sylancl ⊢ φ ∧ p ∈ U → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 ∈ Base R ↾ 𝑠 S
48 22 subrgbas ⊢ S ∈ SubRing ⁡ R → S = Base R ↾ 𝑠 S
49 29 48 syl ⊢ φ ∧ p ∈ U → S = Base R ↾ 𝑠 S
50 47 49 eleqtrrd ⊢ φ ∧ p ∈ U → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 ∈ S
51 50 adantr ⊢ φ ∧ p ∈ U ∧ Y = Q ⁡ p ⁡ X → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 ∈ S
52 0nn0 ⊢ 0 ∈ ℕ 0
53 44 3 2 45 coe1fvalcl ⊢ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ∈ U ∧ 0 ∈ ℕ 0 → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0 ∈ Base R ↾ 𝑠 S
54 42 52 53 sylancl ⊢ φ ∧ p ∈ U → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0 ∈ Base R ↾ 𝑠 S
55 54 49 eleqtrrd ⊢ φ ∧ p ∈ U → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0 ∈ S
56 55 adantr ⊢ φ ∧ p ∈ U ∧ Y = Q ⁡ p ⁡ X → coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0 ∈ S
57 simpr ⊢ φ ∧ p ∈ U ∧ Y = Q ⁡ p ⁡ X → Y = Q ⁡ p ⁡ X
58 1 2 3 4 27 28 29 30 31 10 11 12 13 32 33 34 35 36 37 38 26 rngunsnply1chr2lem3 ⊢ φ ∧ p ∈ U → deg 1 ⁡ R ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ≤ 1 ∧ Q ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ X = Q ⁡ p ⁡ X
59 58 simprd ⊢ φ ∧ p ∈ U → Q ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ X = Q ⁡ p ⁡ X
60 59 adantr ⊢ φ ∧ p ∈ U ∧ Y = Q ⁡ p ⁡ X → Q ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ X = Q ⁡ p ⁡ X
61 eqid ⊢ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1
62 eqid ⊢ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0 = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0
63 58 simpld ⊢ φ ∧ p ∈ U → deg 1 ⁡ R ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ≤ 1
64 2 4 1 3 12 11 44 35 61 62 27 29 42 63 30 evls1degle1 ⊢ φ ∧ p ∈ U → Q ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ X = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0
65 64 adantr ⊢ φ ∧ p ∈ U ∧ Y = Q ⁡ p ⁡ X → Q ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ X = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0
66 57 60 65 3eqtr2d ⊢ φ ∧ p ∈ U ∧ Y = Q ⁡ p ⁡ X → Y = coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 1 · ˙ X + ˙ coe 1 ⁡ p rem 1p ⁡ R ↾ 𝑠 S 2 ⋅ mulGrp P var 1 ⁡ R - P A ⋅ P var 1 ⁡ R + P algSc ⁡ P ⁡ B ⁡ 0
67 19 21 51 56 66 2rspcedvdw ⊢ φ ∧ p ∈ U ∧ Y = Q ⁡ p ⁡ X → ∃ a ∈ S ∃ b ∈ S Y = a · ˙ X + ˙ b
68 1 2 3 4 5 7 8 10 rngunsnply1 ⊢ φ → Y ∈ N ⁡ S ∪ X ↔ ∃ p ∈ U Y = Q ⁡ p ⁡ X
69 9 68 mpbid ⊢ φ → ∃ p ∈ U Y = Q ⁡ p ⁡ X
70 67 69 r19.29a ⊢ φ → ∃ a ∈ S ∃ b ∈ S Y = a · ˙ X + ˙ b