Metamath Proof Explorer


Theorem dchrzrh1

Description: Value of a Dirichlet character at one. (Contributed by Mario Carneiro, 4-May-2016)

Ref Expression
Hypotheses dchrmhm.g 𝐺 = ( DChr ‘ 𝑁 )
dchrmhm.z 𝑍 = ( ℤ/nℤ ‘ 𝑁 )
dchrmhm.b 𝐷 = ( Base ‘ 𝐺 )
dchrelbas4.l 𝐿 = ( ℤRHom ‘ 𝑍 )
dchrzrh1.x ( 𝜑𝑋𝐷 )
Assertion dchrzrh1 ( 𝜑 → ( 𝑋 ‘ ( 𝐿 ‘ 1 ) ) = 1 )

Proof

Step Hyp Ref Expression
1 dchrmhm.g 𝐺 = ( DChr ‘ 𝑁 )
2 dchrmhm.z 𝑍 = ( ℤ/nℤ ‘ 𝑁 )
3 dchrmhm.b 𝐷 = ( Base ‘ 𝐺 )
4 dchrelbas4.l 𝐿 = ( ℤRHom ‘ 𝑍 )
5 dchrzrh1.x ( 𝜑𝑋𝐷 )
6 1 3 dchrrcl ( 𝑋𝐷𝑁 ∈ ℕ )
7 5 6 syl ( 𝜑𝑁 ∈ ℕ )
8 7 nnnn0d ( 𝜑𝑁 ∈ ℕ0 )
9 2 zncrng ( 𝑁 ∈ ℕ0𝑍 ∈ CRing )
10 crngring ( 𝑍 ∈ CRing → 𝑍 ∈ Ring )
11 eqid ( 1r𝑍 ) = ( 1r𝑍 )
12 4 11 zrh1 ( 𝑍 ∈ Ring → ( 𝐿 ‘ 1 ) = ( 1r𝑍 ) )
13 8 9 10 12 4syl ( 𝜑 → ( 𝐿 ‘ 1 ) = ( 1r𝑍 ) )
14 13 fveq2d ( 𝜑 → ( 𝑋 ‘ ( 𝐿 ‘ 1 ) ) = ( 𝑋 ‘ ( 1r𝑍 ) ) )
15 1 2 3 dchrmhm 𝐷 ⊆ ( ( mulGrp ‘ 𝑍 ) MndHom ( mulGrp ‘ ℂfld ) )
16 15 5 sselid ( 𝜑𝑋 ∈ ( ( mulGrp ‘ 𝑍 ) MndHom ( mulGrp ‘ ℂfld ) ) )
17 eqid ( mulGrp ‘ 𝑍 ) = ( mulGrp ‘ 𝑍 )
18 17 11 ringidval ( 1r𝑍 ) = ( 0g ‘ ( mulGrp ‘ 𝑍 ) )
19 eqid ( mulGrp ‘ ℂfld ) = ( mulGrp ‘ ℂfld )
20 cnfld1 1 = ( 1r ‘ ℂfld )
21 19 20 ringidval 1 = ( 0g ‘ ( mulGrp ‘ ℂfld ) )
22 18 21 mhm0 ( 𝑋 ∈ ( ( mulGrp ‘ 𝑍 ) MndHom ( mulGrp ‘ ℂfld ) ) → ( 𝑋 ‘ ( 1r𝑍 ) ) = 1 )
23 16 22 syl ( 𝜑 → ( 𝑋 ‘ ( 1r𝑍 ) ) = 1 )
24 14 23 eqtrd ( 𝜑 → ( 𝑋 ‘ ( 𝐿 ‘ 1 ) ) = 1 )