Metamath Proof Explorer


Theorem subdrgint

Description: The intersection of a nonempty collection of sub division rings is a sub division ring. (Contributed by Thierry Arnoux, 21-Aug-2023)

Ref Expression
Hypotheses subdrgint.1 ⊢ L = R ↾ 𝑠 ⋂ S
subdrgint.2 ⊢ φ → R ∈ DivRing
subdrgint.3 ⊢ φ → S ⊆ SubRing ⁡ R
subdrgint.4 ⊢ φ → S ≠ ∅
subdrgint.5 ⊢ φ ∧ s ∈ S → R ↾ 𝑠 s ∈ DivRing
Assertion subdrgint ⊢ φ → L ∈ DivRing

Proof

Step Hyp Ref Expression
1 subdrgint.1 ⊢ L = R ↾ 𝑠 ⋂ S
2 subdrgint.2 ⊢ φ → R ∈ DivRing
3 subdrgint.3 ⊢ φ → S ⊆ SubRing ⁡ R
4 subdrgint.4 ⊢ φ → S ≠ ∅
5 subdrgint.5 ⊢ φ ∧ s ∈ S → R ↾ 𝑠 s ∈ DivRing
6 subrgint ⊢ S ⊆ SubRing ⁡ R ∧ S ≠ ∅ → ⋂ S ∈ SubRing ⁡ R
7 3 4 6 syl2anc ⊢ φ → ⋂ S ∈ SubRing ⁡ R
8 1 subrgring ⊢ ⋂ S ∈ SubRing ⁡ R → L ∈ Ring
9 7 8 syl ⊢ φ → L ∈ Ring
10 1 fveq2i ⊢ mulGrp L = mulGrp R ↾ 𝑠 ⋂ S
11 10 oveq1i ⊢ mulGrp L ↾ 𝑠 Base L ∖ 0 L = mulGrp R ↾ 𝑠 ⋂ S ↾ 𝑠 Base L ∖ 0 L
12 eqid ⊢ R ↾ 𝑠 ⋂ S = R ↾ 𝑠 ⋂ S
13 eqid ⊢ mulGrp R = mulGrp R
14 12 13 mgpress ⊢ R ∈ DivRing ∧ ⋂ S ∈ SubRing ⁡ R → mulGrp R ↾ 𝑠 ⋂ S = mulGrp R ↾ 𝑠 ⋂ S
15 2 7 14 syl2anc ⊢ φ → mulGrp R ↾ 𝑠 ⋂ S = mulGrp R ↾ 𝑠 ⋂ S
16 15 oveq1d ⊢ φ → mulGrp R ↾ 𝑠 ⋂ S ↾ 𝑠 Base L ∖ 0 L = mulGrp R ↾ 𝑠 ⋂ S ↾ 𝑠 Base L ∖ 0 L
17 difssd ⊢ φ → Base L ∖ 0 L ⊆ Base L
18 eqid ⊢ Base R = Base R
19 18 subrgss ⊢ ⋂ S ∈ SubRing ⁡ R → ⋂ S ⊆ Base R
20 1 18 ressbas2 ⊢ ⋂ S ⊆ Base R → ⋂ S = Base L
21 7 19 20 3syl ⊢ φ → ⋂ S = Base L
22 17 21 sseqtrrd ⊢ φ → Base L ∖ 0 L ⊆ ⋂ S
23 ressabs ⊢ ⋂ S ∈ SubRing ⁡ R ∧ Base L ∖ 0 L ⊆ ⋂ S → mulGrp R ↾ 𝑠 ⋂ S ↾ 𝑠 Base L ∖ 0 L = mulGrp R ↾ 𝑠 Base L ∖ 0 L
24 7 22 23 syl2anc ⊢ φ → mulGrp R ↾ 𝑠 ⋂ S ↾ 𝑠 Base L ∖ 0 L = mulGrp R ↾ 𝑠 Base L ∖ 0 L
25 16 24 eqtr3d ⊢ φ → mulGrp R ↾ 𝑠 ⋂ S ↾ 𝑠 Base L ∖ 0 L = mulGrp R ↾ 𝑠 Base L ∖ 0 L
26 intiin ⊢ ⋂ S = ⋂ s ∈ S s
27 21 26 eqtr3di ⊢ φ → Base L = ⋂ s ∈ S s
28 27 difeq1d ⊢ φ → Base L ∖ 0 L = ⋂ s ∈ S s ∖ 0 L
29 28 oveq2d ⊢ φ → mulGrp R ↾ 𝑠 Base L ∖ 0 L = mulGrp R ↾ 𝑠 ⋂ s ∈ S s ∖ 0 L
30 vex ⊢ s ∈ V
31 30 difexi ⊢ s ∖ 0 L ∈ V
32 31 dfiin3 ⊢ ⋂ s ∈ S s ∖ 0 L = ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L
33 iindif1 ⊢ S ≠ ∅ → ⋂ s ∈ S s ∖ 0 L = ⋂ s ∈ S s ∖ 0 L
34 4 33 syl ⊢ φ → ⋂ s ∈ S s ∖ 0 L = ⋂ s ∈ S s ∖ 0 L
35 32 34 eqtr3id ⊢ φ → ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L = ⋂ s ∈ S s ∖ 0 L
36 35 oveq2d ⊢ φ → mulGrp R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L = mulGrp R ↾ 𝑠 ⋂ s ∈ S s ∖ 0 L
37 difss ⊢ Base R ∖ 0 R ⊆ Base R
38 eqid ⊢ mulGrp R ↾ 𝑠 Base R ∖ 0 R = mulGrp R ↾ 𝑠 Base R ∖ 0 R
39 13 18 mgpbas ⊢ Base R = Base mulGrp R
40 38 39 ressbas2 ⊢ Base R ∖ 0 R ⊆ Base R → Base R ∖ 0 R = Base mulGrp R ↾ 𝑠 Base R ∖ 0 R
41 37 40 ax-mp ⊢ Base R ∖ 0 R = Base mulGrp R ↾ 𝑠 Base R ∖ 0 R
42 41 fvexi ⊢ Base R ∖ 0 R ∈ V
43 iinssiun ⊢ S ≠ ∅ → ⋂ s ∈ S s ∖ 0 L ⊆ ⋃ s ∈ S s ∖ 0 L
44 4 43 syl ⊢ φ → ⋂ s ∈ S s ∖ 0 L ⊆ ⋃ s ∈ S s ∖ 0 L
45 subrgsubg ⊢ s ∈ SubRing ⁡ R → s ∈ SubGrp ⁡ R
46 45 ssriv ⊢ SubRing ⁡ R ⊆ SubGrp ⁡ R
47 3 46 sstrdi ⊢ φ → S ⊆ SubGrp ⁡ R
48 subgint ⊢ S ⊆ SubGrp ⁡ R ∧ S ≠ ∅ → ⋂ S ∈ SubGrp ⁡ R
49 47 4 48 syl2anc ⊢ φ → ⋂ S ∈ SubGrp ⁡ R
50 eqid ⊢ 0 R = 0 R
51 1 50 subg0 ⊢ ⋂ S ∈ SubGrp ⁡ R → 0 R = 0 L
52 49 51 syl ⊢ φ → 0 R = 0 L
53 52 adantr ⊢ φ ∧ s ∈ S → 0 R = 0 L
54 53 sneqd ⊢ φ ∧ s ∈ S → 0 R = 0 L
55 54 difeq2d ⊢ φ ∧ s ∈ S → s ∖ 0 R = s ∖ 0 L
56 3 sselda ⊢ φ ∧ s ∈ S → s ∈ SubRing ⁡ R
57 18 subrgss ⊢ s ∈ SubRing ⁡ R → s ⊆ Base R
58 56 57 syl ⊢ φ ∧ s ∈ S → s ⊆ Base R
59 58 ssdifd ⊢ φ ∧ s ∈ S → s ∖ 0 R ⊆ Base R ∖ 0 R
60 55 59 eqsstrrd ⊢ φ ∧ s ∈ S → s ∖ 0 L ⊆ Base R ∖ 0 R
61 60 iunssd ⊢ φ → ⋃ s ∈ S s ∖ 0 L ⊆ Base R ∖ 0 R
62 44 61 sstrd ⊢ φ → ⋂ s ∈ S s ∖ 0 L ⊆ Base R ∖ 0 R
63 32 62 eqsstrrid ⊢ φ → ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ⊆ Base R ∖ 0 R
64 ressabs ⊢ Base R ∖ 0 R ∈ V ∧ ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ⊆ Base R ∖ 0 R → mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L = mulGrp R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L
65 42 63 64 sylancr ⊢ φ → mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L = mulGrp R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L
66 18 50 38 drngmgp ⊢ R ∈ DivRing → mulGrp R ↾ 𝑠 Base R ∖ 0 R ∈ Grp
67 2 66 syl ⊢ φ → mulGrp R ↾ 𝑠 Base R ∖ 0 R ∈ Grp
68 67 adantr ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 Base R ∖ 0 R ∈ Grp
69 60 41 sseqtrdi ⊢ φ ∧ s ∈ S → s ∖ 0 L ⊆ Base mulGrp R ↾ 𝑠 Base R ∖ 0 R
70 ressabs ⊢ Base R ∖ 0 R ∈ V ∧ s ∖ 0 L ⊆ Base R ∖ 0 R → mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 s ∖ 0 L = mulGrp R ↾ 𝑠 s ∖ 0 L
71 42 60 70 sylancr ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 s ∖ 0 L = mulGrp R ↾ 𝑠 s ∖ 0 L
72 eqid ⊢ R ↾ 𝑠 s = R ↾ 𝑠 s
73 72 13 mgpress ⊢ R ∈ DivRing ∧ s ∈ S → mulGrp R ↾ 𝑠 s = mulGrp R ↾ 𝑠 s
74 2 73 sylan ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s = mulGrp R ↾ 𝑠 s
75 55 eqcomd ⊢ φ ∧ s ∈ S → s ∖ 0 L = s ∖ 0 R
76 74 75 oveq12d ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s ↾ 𝑠 s ∖ 0 L = mulGrp R ↾ 𝑠 s ↾ 𝑠 s ∖ 0 R
77 simpr ⊢ φ ∧ s ∈ S → s ∈ S
78 difssd ⊢ φ ∧ s ∈ S → s ∖ 0 L ⊆ s
79 ressabs ⊢ s ∈ S ∧ s ∖ 0 L ⊆ s → mulGrp R ↾ 𝑠 s ↾ 𝑠 s ∖ 0 L = mulGrp R ↾ 𝑠 s ∖ 0 L
80 77 78 79 syl2anc ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s ↾ 𝑠 s ∖ 0 L = mulGrp R ↾ 𝑠 s ∖ 0 L
81 76 80 eqtr3d ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s ↾ 𝑠 s ∖ 0 R = mulGrp R ↾ 𝑠 s ∖ 0 L
82 72 18 ressbas2 ⊢ s ⊆ Base R → s = Base R ↾ 𝑠 s
83 56 57 82 3syl ⊢ φ ∧ s ∈ S → s = Base R ↾ 𝑠 s
84 72 50 subrg0 ⊢ s ∈ SubRing ⁡ R → 0 R = 0 R ↾ 𝑠 s
85 56 84 syl ⊢ φ ∧ s ∈ S → 0 R = 0 R ↾ 𝑠 s
86 85 sneqd ⊢ φ ∧ s ∈ S → 0 R = 0 R ↾ 𝑠 s
87 83 86 difeq12d ⊢ φ ∧ s ∈ S → s ∖ 0 R = Base R ↾ 𝑠 s ∖ 0 R ↾ 𝑠 s
88 87 oveq2d ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s ↾ 𝑠 s ∖ 0 R = mulGrp R ↾ 𝑠 s ↾ 𝑠 Base R ↾ 𝑠 s ∖ 0 R ↾ 𝑠 s
89 eqid ⊢ Base R ↾ 𝑠 s = Base R ↾ 𝑠 s
90 eqid ⊢ 0 R ↾ 𝑠 s = 0 R ↾ 𝑠 s
91 eqid ⊢ mulGrp R ↾ 𝑠 s ↾ 𝑠 Base R ↾ 𝑠 s ∖ 0 R ↾ 𝑠 s = mulGrp R ↾ 𝑠 s ↾ 𝑠 Base R ↾ 𝑠 s ∖ 0 R ↾ 𝑠 s
92 89 90 91 drngmgp ⊢ R ↾ 𝑠 s ∈ DivRing → mulGrp R ↾ 𝑠 s ↾ 𝑠 Base R ↾ 𝑠 s ∖ 0 R ↾ 𝑠 s ∈ Grp
93 5 92 syl ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s ↾ 𝑠 Base R ↾ 𝑠 s ∖ 0 R ↾ 𝑠 s ∈ Grp
94 88 93 eqeltrd ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s ↾ 𝑠 s ∖ 0 R ∈ Grp
95 81 94 eqeltrrd ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 s ∖ 0 L ∈ Grp
96 71 95 eqeltrd ⊢ φ ∧ s ∈ S → mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 s ∖ 0 L ∈ Grp
97 eqid ⊢ Base mulGrp R ↾ 𝑠 Base R ∖ 0 R = Base mulGrp R ↾ 𝑠 Base R ∖ 0 R
98 97 issubg ⊢ s ∖ 0 L ∈ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R ↔ mulGrp R ↾ 𝑠 Base R ∖ 0 R ∈ Grp ∧ s ∖ 0 L ⊆ Base mulGrp R ↾ 𝑠 Base R ∖ 0 R ∧ mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 s ∖ 0 L ∈ Grp
99 68 69 96 98 syl3anbrc ⊢ φ ∧ s ∈ S → s ∖ 0 L ∈ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R
100 99 ralrimiva ⊢ φ → ∀ s ∈ S s ∖ 0 L ∈ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R
101 eqid ⊢ s ∈ S ⟼ s ∖ 0 L = s ∈ S ⟼ s ∖ 0 L
102 101 rnmptss ⊢ ∀ s ∈ S s ∖ 0 L ∈ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R → ran ⁡ s ∈ S ⟼ s ∖ 0 L ⊆ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R
103 100 102 syl ⊢ φ → ran ⁡ s ∈ S ⟼ s ∖ 0 L ⊆ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R
104 dmmptg ⊢ ∀ s ∈ S s ∖ 0 L ∈ V → dom ⁡ s ∈ S ⟼ s ∖ 0 L = S
105 difexg ⊢ s ∈ S → s ∖ 0 L ∈ V
106 104 105 mprg ⊢ dom ⁡ s ∈ S ⟼ s ∖ 0 L = S
107 106 a1i ⊢ φ → dom ⁡ s ∈ S ⟼ s ∖ 0 L = S
108 107 4 eqnetrd ⊢ φ → dom ⁡ s ∈ S ⟼ s ∖ 0 L ≠ ∅
109 dm0rn0 ⊢ dom ⁡ s ∈ S ⟼ s ∖ 0 L = ∅ ↔ ran ⁡ s ∈ S ⟼ s ∖ 0 L = ∅
110 109 necon3bii ⊢ dom ⁡ s ∈ S ⟼ s ∖ 0 L ≠ ∅ ↔ ran ⁡ s ∈ S ⟼ s ∖ 0 L ≠ ∅
111 108 110 sylib ⊢ φ → ran ⁡ s ∈ S ⟼ s ∖ 0 L ≠ ∅
112 subgint ⊢ ran ⁡ s ∈ S ⟼ s ∖ 0 L ⊆ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R ∧ ran ⁡ s ∈ S ⟼ s ∖ 0 L ≠ ∅ → ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ∈ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R
113 103 111 112 syl2anc ⊢ φ → ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ∈ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R
114 eqid ⊢ mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L = mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L
115 114 subggrp ⊢ ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ∈ SubGrp ⁡ mulGrp R ↾ 𝑠 Base R ∖ 0 R → mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ∈ Grp
116 113 115 syl ⊢ φ → mulGrp R ↾ 𝑠 Base R ∖ 0 R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ∈ Grp
117 65 116 eqeltrrd ⊢ φ → mulGrp R ↾ 𝑠 ⋂ ran ⁡ s ∈ S ⟼ s ∖ 0 L ∈ Grp
118 36 117 eqeltrrd ⊢ φ → mulGrp R ↾ 𝑠 ⋂ s ∈ S s ∖ 0 L ∈ Grp
119 29 118 eqeltrd ⊢ φ → mulGrp R ↾ 𝑠 Base L ∖ 0 L ∈ Grp
120 25 119 eqeltrd ⊢ φ → mulGrp R ↾ 𝑠 ⋂ S ↾ 𝑠 Base L ∖ 0 L ∈ Grp
121 11 120 eqeltrid ⊢ φ → mulGrp L ↾ 𝑠 Base L ∖ 0 L ∈ Grp
122 eqid ⊢ Base L = Base L
123 eqid ⊢ 0 L = 0 L
124 eqid ⊢ mulGrp L ↾ 𝑠 Base L ∖ 0 L = mulGrp L ↾ 𝑠 Base L ∖ 0 L
125 122 123 124 isdrng2 ⊢ L ∈ DivRing ↔ L ∈ Ring ∧ mulGrp L ↾ 𝑠 Base L ∖ 0 L ∈ Grp
126 9 121 125 sylanbrc ⊢ φ → L ∈ DivRing