Metamath Proof Explorer


Theorem 1idl

Description: Obsolete theorem, use 2idl1el instead. Two ways of expressing the unit ideal. (Contributed by Jeff Madsen, 10-Jun-2010) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypotheses 1idl.1 ⊢ G = 1 st ⁡ R
1idl.2 ⊢ H = 2 nd ⁡ R
1idl.3 ⊢ X = ran ⁡ G
1idl.4 ⊢ U = GId ⁡ H
Assertion 1idl ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R → U ∈ I ↔ I = X

Proof

Step Hyp Ref Expression
1 1idl.1 ⊢ G = 1 st ⁡ R
2 1idl.2 ⊢ H = 2 nd ⁡ R
3 1idl.3 ⊢ X = ran ⁡ G
4 1idl.4 ⊢ U = GId ⁡ H
5 1 3 idlss ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R → I ⊆ X
6 5 adantr ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R ∧ U ∈ I → I ⊆ X
7 1 rneqi ⊢ ran ⁡ G = ran ⁡ 1 st ⁡ R
8 3 7 eqtri ⊢ X = ran ⁡ 1 st ⁡ R
9 2 8 4 rngolidm ⊢ R ∈ RingOps ∧ x ∈ X → U H x = x
10 9 ad2ant2rl ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R ∧ U ∈ I ∧ x ∈ X → U H x = x
11 1 2 3 idlrmulcl ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R ∧ U ∈ I ∧ x ∈ X → U H x ∈ I
12 10 11 eqeltrrd ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R ∧ U ∈ I ∧ x ∈ X → x ∈ I
13 12 expr ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R ∧ U ∈ I → x ∈ X → x ∈ I
14 13 ssrdv ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R ∧ U ∈ I → X ⊆ I
15 6 14 eqssd ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R ∧ U ∈ I → I = X
16 15 ex ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R → U ∈ I → I = X
17 8 2 4 rngo1cl ⊢ R ∈ RingOps → U ∈ X
18 17 adantr ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R → U ∈ X
19 eleq2 ⊢ I = X → U ∈ I ↔ U ∈ X
20 18 19 syl5ibrcom ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R → I = X → U ∈ I
21 16 20 impbid ⊢ R ∈ RingOps ∧ I ∈ Idl ⁡ R → U ∈ I ↔ I = X