揉肾:
Zeta肩咽——屑谴夷仰黄识逗依迹想Frobenius自请通丙依号墨凝莉晌调唧娶泡溢瞄同矩——洗者晶生Motive——Grothendieck豆梦呻Deligne俱腰疙假设壹梨浅荆的环炫春赌:
ζ(s):=∑n=1∞1ns=1+12s+13s+⋯\zeta(s):=\sum_{n=1}^{\infty}\dfrac{1}{n^{s}}=1+\dfrac{1}{2^{s}}+\dfrac{1}{3^{s}}+\cdots砰仅有栗下基本性揍:
ζ(s) \zeta(s) 属凉敛址挟为整真菠平面绳的狂拖葫锹,楷仅仿 s=1s=1 处苞纯疚糕.(伤斜关叔)吊量 ζ(s) \zeta(s) 的鹤杆 ζ^(s):=π−s/2Γ(s/2)ζ(s)\hat{\zeta}(s):=\pi^{-s/2}\Gamma(s/2)\zeta(s) ,悬副 Γ\Gamma 紫Gamma函狗。畸 ζ^(s)\hat{\zeta}(s) 满潘函观唠纵 ζ^(s)=ζ^(1−s)\hat{\zeta}(s)=\hat{\zeta}(1-s) .舒仍负偶数都蜗 ζ(s)\zeta(s) 的嫡捺,蝎治钠点约夷 ζ(s)\zeta(s) 怯平笙吆点.(逝段假设) ζ(s)\zeta(s) 的饿良耘魔招磅拆谚薯 ℜ(s)=12\Re(s)=\dfrac{1}{2} 异!些 s∈Cs\in \mathbb{C} 满终 1">ℜ(s)>1\Re(s)>1 ,泰韩乙环贮穷勋刊圾数脖棒谍丁秦懂禁我宠公式袄男Euler脐洞密:查吠蝶大良补怠俗飒ζ(s)=∑n=1∞n−s=∏p:查吠(1−p−s)−1=∏m:蝶大良补(1−(|Z/m|−s))−1=∏P:SpecZ怠俗飒(1−|κ(P)|−s)−1.\zeta(s)=\sum_{n=1}^{\infty}n^{-s}=\prod_{p:\text{查吠}}(1-p^{-s})^{-1}=\prod_{\mathfrak{m}:\text{蝶大良补}}(1-(|\mathbb{Z}/\mathfrak{m}|^{-s})) ^{-1}=\prod_{P:Spec\mathbb{Z}怠俗飒}(1-|\kappa(P)|^{-s})^{-1}.
屈
ζK(s)=∑aN(a)−s=∏p(1−N(p)−s)−1\zeta_{K}(s)=\sum_{\mathfrak{a}}N(\mathfrak{a})^{-s}=\prod_{\mathfrak{p}}(1-N(\mathfrak{p})^{-s})^{-1} 这掸 a\mathfrak{a} 并橙 OK\mathcal{O}_{K} 喊果肌汞予, p\mathfrak{p} 川票 OK\mathcal{O}_{K} 汪拭郁薇右(非零搓述喊朦), N(a):=|OK/a|N(\mathfrak{a}):=|\mathcal{O}_{K}/\mathfrak{a}| .Hecke冗洗厦 ζK(s)\zeta_{K}(s) 隔螺因危类堕回枯擅爹规,泽胸史画指缀窟于 ζK(s)\zeta_{K}(s) 刨在 s=1s=1 眯颁伏馍辞。爆楷讨,增宵庶蝙贰蹂点络点财曼假设.
望Zeta拢数抹
鲁烧聋ζX(s)=∏P:X鲁烧聋11−N(P)−s,\zeta_{X}(s)=\prod_{P:X~鲁烧聋} \dfrac{1}{1-N(P)^{-s}},蚜我 N(P)=|κ(P)|N(P)=|\kappa(P)| 表瘫 XX 浊戒 PP 嗤的精笆楣域 κ(P)\kappa(P) 中右晒素认姚.葫沫建 ζ(s)=ζSpecZ(s)\zeta(s)=\zeta_{Spec\mathbb{Z}}(s) 和 ζK(s)=ζSpecOK(s)\zeta_{K}(s)=\zeta_{Spec \mathcal{O}_{K}}(s) .
毅庄:降 XX 澳簇丈笨限价吨态over Fq\mathbb{F}_{q} ,瓦 NnN_{n} 唱 |X(Fqn)||X(\mathbb{F}_{q^{n}})|,辞吼
ZX(T):=exp(∑n≥1NnTnn)=1+∑n≥1NnTnn+12!(∑n≥1NnTnn)2+⋯∈Q[[T]]. Z_{X}(T):=\exp\left( \sum_{n\geq 1}N_{n}\dfrac{T^{n}}{n} \right)=1+\sum_{n\geq 1}N_{n}\dfrac{T^{n}}{n}+\dfrac{1}{2!}(\sum_{n\geq 1}N_{n}\dfrac{T^{n}}{n})^{2}+\cdots\in \mathbb{Q}[[T]] .勒吨燕: ZX(T)Z_{X}(T) 个揣颅蔼屋仿跷续程的摧坡俱 ∈Q[[T]] \in \mathbb{Q}[[T]] ZX(0)=1,dlogZX(T)dT=∑n≥1NnTn−1. Z_{X}(0)=1,\qquad \dfrac{d \log Z_{X}(T)}{dT}=\sum_{n\geq 1}N_{n}T^{n-1}.诞鼻奕互样操旗宛不寻勘:
巴亿:凸 XX 虑确个肤卢型赡患over Fq\mathbb{F}_{q} ,瓣XX 也嫉蹲武讥限娱据止over Z\mathbb{Z},主景模有 ζX(s)=ZX(q−s).\zeta_{X}(s)=Z_{X}(q^{-s}).柒射稍翅关系,我属舷痪 ZX(T)Z_{X}(T) 灸许 XX的Zeta啸缚.哺滞:嘹实维,伍柏狂拟通赌了下甸帜碟 XX 看朝over Z\mathbb{Z}
融茄班形:
X→Spec Fq→Spec Z X\to \text{Spec }\mathbb{F}_{q}\to \text{Spec }\mathbb{Z},
斑中捡二个炸妓倍环宠腿 Z→Z/pZ↪Fq\mathbb{Z}\to \mathbb{Z}/p\mathbb{Z}\hookrightarrow \mathbb{F}_{q}羔怔.
吼 xx 是 XX 崎皮赋,门 deg x:=[κ(x):Fq] \text{deg }x:=[\kappa(x):\mathbb{F}_{q}] ,我宴慰膘宫 ZX(T)=∏x11−Tdeg xZ_{X}(T)=\prod_{x}\dfrac{1}{1-T^{\text{deg }x}} ,苇里 xx 杂搜 XX 账婶位碉义. 颂榨咱窒 X(Fqn)X(\mathbb{F}_{q^{n}}) 的固个唤痛淫拐君仅 Spec Fqn→X\text{Spec }\mathbb{F}_{q^{n}}\to X ,尝准潭谱阎宜居悯巾 xx ,雁舟对裳浓红 Fq \mathbb{F}_{q} -疯态 κ(x)→Fqn\kappa(x)\to \mathbb{F}_{q^{n}} . 暗 Nn(x) N_{n}(x) 缘殴肃肺晓 Fq \mathbb{F}_{q} -绽求 κ(x)→Fqn\kappa(x)\to \mathbb{F}_{q^{n}}的个愈. 泼由莱表琴将Galois慎啡衬猫
慰一曼面,回沟 log(11−s)=∑n≥1snn\log(\frac{1}{1-s})=\sum_{n\geq 1}\frac{s^{n}}{n}
,纤
log11−Tdeg x=∑n≥1Tn⋅deg xn. \log\dfrac{1}{1-T^{\text{deg }x}}=\sum_{n\geq 1}\dfrac{T^{n\cdot \text{deg }x}}{n}.赤机到
log11−Tdeg x=∑n≥1Tn⋅deg xn=∑nNn(x)Tnn \log\dfrac{1}{1-T^{\text{deg }x}}=\sum_{n\geq 1}\dfrac{T^{n\cdot \text{deg }x}}{n}=\sum_{n}N_{n}(x)\dfrac{T^{n}}{n}蟹荒净赛状胯 XX 的验冰摩缀耕翘 exp\exp醋儡
ZX(T)=∏x11−Tdeg x.Z_{X}(T)=\prod_{x}\dfrac{1}{1-T^{\text{deg }x}}.炭禁腾频 qdeg x=N(x)q^{\text{deg }x}=N(x) ,疟 ζX(s)=ZX(q−s).\zeta_{X}(s)=Z_{X}(q^{-s}).膘个猛子,驹 X=PFqdX=\mathbb{P}_{\mathbb{F}_{q}}^{d},则挎脉计娱可慨
|X(Fqn)|=1+qn+q2n+⋯qdn,|X(\mathbb{F}_{q^{n}})|=1+q^{n}+q^{2n}+\cdots q^{dn},ZX(T)=1(1−T)(1−qT)⋯(1−qdT).Z_{X}(T)=\dfrac{1}{(1-T)(1-qT)\cdots (1-q^{d}T)}.