Questions tagged [iwasawa-theory]

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How to approach the Mazur-Wiles paper on Iwasawa theory?

I would like to read and understand the Mazur-Wiles paper on Iwasawa theory: "Class Fields of Abelian Extensions of $\Bbb Q$". What would be the right way to approach this paper? Currently, my ...
Asvin's user avatar
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9 votes
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744 views

Existence of multi-variable $p$-adic $L$-functions

What's the "state of the art" in constructing multi-variable p-adic L-functions for number fields? More precisely: if K is a number field, and $K_{\infty} / K$ is an infinite Galois extension, ...
David Loeffler's user avatar
7 votes
0 answers
161 views

$\lambda$-invariants in cyclotomic $\mathbb{Z}_p$ extensions

The idea that Selmer groups and class groups are related is not new. More recently, we understand that the growth patterns of fine Selmer groups are very similar to that of class groups in cyclotomic $...
debanjana's user avatar
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7 votes
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List of applications of the Deformation theory of Galois Representations in contexts other that $R=T$

The Deformation theory of Galois representations developed by Mazur has been extensively used in proving that Galois representations with special properties are modular/automorphic through the ...
user avatar
6 votes
1 answer
582 views

How hard is it to find the first layer of this basic $\mathbb{Z}_p$-extension?

$\DeclareMathOperator\Gal{Gal}$Let $p$ be a prime number and $\zeta_{p^n}$ be a primitive $p^n$-th root of unity. We know that there is a unique subfield $\mathbb{Q}_1$ of $\mathbb{Q}(\zeta_{p^2})$ ...
matt stokes's user avatar
6 votes
0 answers
279 views

Derivatives of p-adic L-functions of modular forms

Let $f$ be a eigen-newform and $p$ is a good prime for $f$. We know that the $p$-adic $L$-function of $f$ interpolates the complex $L$-values of $f$ when evaluated at Dirichlet characters. My ...
user119481's user avatar
6 votes
0 answers
210 views

Structure theorem for modules over multi-variable Iwasawa algebras

It is well-known that if $\Lambda=Z_p[[X]]$ and $M$ a finitely generated $\Lambda$-module, then $M$ is pseudo-isomorphic to $$ \Lambda^{\oplus r}\oplus\bigoplus_{i=1}^s\Lambda/(F_i) $$ for some ...
user119481's user avatar
6 votes
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291 views

Iwasawa theory, $\mathbb{Z}_p^{2}$-extension, Greenberg module

Take $H\subset \bar{\mathbb{Q}}$ be a quartic imaginary number field such that $\operatorname{Gal}(H/\mathbb{Q})=\mathbb{Z}_2 \times \mathbb{Z}_2$. Denote by $F$ the quadratic real subfield of $H$ and ...
Adel BETINA's user avatar
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5 votes
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Why does passing to a $\mathbf{Z}_p$-extension make things easier?

In Iwasawa theory, even if one is only interested in questions about a number field $K$ (e.g. class groups of $\mathbf{Q}(\mu_p)$, Selmer groups of abelian varieties over $\mathbf{Q}$), to prove deep ...
user471019's user avatar
5 votes
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Structure of finitely generated $\mathbb{Z}/p^n\mathbb{Z}[[S,T]]$-modules

Let $\Omega=\mathbb{Z}/p\mathbb{Z}[[S,T]]$. $\Omega$ is a commutative, Noetherian and integrally closed domain of Krull dimension 2. According to Bourbaki's commutative algebra VII $\S 4$, if $M$ is a ...
Ahmed Matar's user avatar
5 votes
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Is there a converse to Vatsal's theorem on congruence of p-adic L-functions?

Let $f=\sum_n a_n(f) q^n$ and $g=\sum_n a_n(g) q^n$ be normalized (cuspidal) newforms whose Fourier coefficients are contained in the p-adic field K for which the uniformizer of $\mathcal{O}_K$ is ...
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5 votes
0 answers
241 views

$\mu=0$ for CM Elliptic curves?

Let $E$ be an elliptic curve defined over $F$ with CM by $\mathcal{O}_K$ where $K$ is an imaginary quadratic field. We may assume the $F$ contains $K$ and also contains the $p$-division points, where $...
debanjana's user avatar
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From which layer we can apply Iwasawa's class number formula in Z_p extension?

Let $K$ be a number field. Let $K_\infty/K$ be a $\mathbb{Z}_p$ extension. Iwasawa proved that there are four integers $n_0,\mu,\lambda,\nu \geq 0$ such that for any $n\geq n_0$, $$\mathrm{ord}_p(...
J.Li's user avatar
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When can one expect that the $\mu$-invariant of a $\mathbb{Z}_p$-extension of a number field is zero?

What is special about $\mathbb{Z}_p$-extensions which are motivic to ensure that their $\mu$ invariant is zero? Is there a simple conceptual reason. Here are some examples. Let $F$ be a totally real ...
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non $p$ part of the class group and analogous results

Washington had proven in 1978 that for $q$ a prime ($q \neq p$), if $q^{e_n}$ exactly divides the class number of $\mathbb{Q}_n$, ie the $n$-th layer in the cyclotomic $\mathbb{Z}_p$ extension, then $...
debanjana's user avatar
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For Hida theory on $GU(2,2)$ can $p$ be inert in the imaginary quadratic field $K$?

I am familiar with the theory of Hida families of modular forms, so Hida theory on $GL_2$, but I am not familiar with Hida theory on any other algebraic groups. My question concerns Hida families of ...
Will Dukeminier's user avatar
4 votes
0 answers
185 views

Alternative formulation of the Ferrero-Washington Theorem

The Ferrero-Washington theorem says that if $K/\mathbf{Q}$ is an abelian extension, then the cyclotomic $\mathbf{Z}_p$ extension $K^{\text{cyc}}/K$ has $\mu=0$. In the paper "Iwasawa invariants ...
Adithya Chakravarthy's user avatar
4 votes
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257 views

The Gamma-transform and $p$-adic $L$-functions

I'm currently reading the paper "On the $\mu$-invariant of the $\Gamma$-transform of a rational function" by W Sinnott. In this paper, he gives an alternate proof that $\mu=0$ for abelian ...
Adithya Chakravarthy's user avatar
4 votes
0 answers
152 views

Average size of class groups of cyclotomic fields: three perspectives

Let $K$ be a number field. Let $h(K)$ denote the class number (i.e., the size of the ideal class group) of $K$, $R(K)$ be the regulator of $K$, and $\Delta_K$ the discriminant of $K$. Let $\mathcal{F}$...
Stanley Yao Xiao's user avatar
4 votes
0 answers
219 views

Calculating some Galois cohomology

Let $L/\mathbb{Q}$ be a Galois extension of degree $p$ and $E$ be an elliptic curve defined over $\mathbb{Q}$. Let $p$ be a fixed prime (of good ordinary reduction if required). We use $L_\infty, \...
debanjana's user avatar
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4 votes
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History of the relation between $p$-adic measures and power series

In 1964, Kubota and Leopoldt defined the $p$-adic $L$-function by means of some $p$-adic sums (now called the Volkenborn integral which is a $p$-adic distribution). Later, Mazur (in his secret ...
efs's user avatar
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4 votes
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189 views

Restricted Iwasawa theory

Let $p$ be a prime number, let $K$ be a number field, and let $L$ be a Galois extension of $K$ such that the Galois group $\Gamma$ of $L$ over $K$ is (continuously) isomorphic to the (additive) group $...
Pablo's user avatar
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4 votes
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Structure of modules over Iwasawa algebra $\mathbb{Z}_p[[T]]$ when taken mod $p$

Let $A \in M_n(\mathbb{Z}_p)$ be a nonsingular matrix which is nilpotent mod $p$, so $A^r \in pM_n(\mathbb{Z}_p)$ for some $r$. Then $\mathbb{Z}_p[[T]]$ acts on $\mathbb{Z}_p^n$ with $T$ acting by $A$....
Roger Van Peski's user avatar
3 votes
0 answers
202 views

Generalisation of Sharifi's conjecture for Siegel varieties

I recently learned Sharifi's conjecture in this article by F.Takako and K.Kato. According to my understanding, this conjecture states that (the conjugation invariant) of the projective limit $\...
Marsault Chabat's user avatar
3 votes
0 answers
178 views

Extending the analogy between cyclotomic units and elliptic units

There is a nice analogy between cyclotomic units and elliptic units given as follows: Cyclotomic units are related to special values of the Riemann Zeta function. This is because the logarithmic ...
Adithya Chakravarthy's user avatar
3 votes
0 answers
129 views

question about Sinnott's proof of the Ferrero-Washington Theorem

I'm currently reading the paper "On the $\mu$-invariant of the Γ-transform of a rational function" by W Sinnott. In this paper, he gives an alternate proof that $\mu=0$ for abelian number ...
Adithya Chakravarthy's user avatar
3 votes
0 answers
149 views

Relationship between fine Selmer groups and class groups

Given an elliptic curve $E_{/\mathbb{Q}}$ and an odd prime number $p$, let $S$ be the set of primes consisting of $p$ and the primes at which $E$ has bad reduction. The fine Selmer group $R_{p^\infty}(...
Anwesh Ray's user avatar
3 votes
0 answers
139 views

What do congruences between modular forms tell us about $\mu$-invariants of elliptic curves?

This question is based off these notes by Preston Wake about Iwasawa invariants and Hida Families. In the notes, the author asks "why" the elliptic curve $11A3$ has $\mu$-invariant equal to $...
Adithya Chakravarthy's user avatar
3 votes
0 answers
152 views

Finiteness of points over the cyclotomic extension for modular forms

Let $\rho(f):G_\mathbb{Q} \rightarrow GL_2(K_f)$ be the Galois representation attached to some cuspidal modular form $f$ where $K_f$ is a finite extension of $\mathbb{Q}_p$. Let $V_f$ be the vector ...
user100603's user avatar
3 votes
0 answers
107 views

Regular growth of ranks in Iwasawa tower

$\newcommand{\rank}{\operatorname{rank}}$Let $G=H \times K$ be a torsion free pro-$p$, $p$-adic Lie group. Let $H =\mathbb{Z}_p$, the ring of $p$-adic integers and $K$ is a non-commutative torsion ...
user100603's user avatar
3 votes
0 answers
145 views

Iwasawa theory and cohomological $p$-dimension of Inertia

Let $E$ be a elliptic curve without complex multiplication over a number field $F$. Let $F_n=F[E_{p^n}]$ and $F_{\infty}=F[E_{p^\infty}]$. So by a well know theorem of Serre, the Galois group $Gal(F_\...
MathStudent's user avatar
3 votes
0 answers
61 views

How does the $\lambda$ invariant propagate with extra ramification?

Let $\mathbb{Q}^{cyc}$ denote the cyclotomic $\mathbb{Z}_p$ extension of $\mathbb{Q}$ and let $\Lambda$ denote the corresponding Iwasawa algebra. Let $p$ be a prime. Let $S$ denote a finite set of ...
user avatar
3 votes
0 answers
126 views

Some Questions regarding the fine Shafarevich-Tate group

The fine Shafarevich-Tate (ST) group appears to not have been studied in much depth except for one paper by Wuthrich (2007). However, it only talks about fine ST group for elliptic curves, which makes ...
debanjana's user avatar
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3 votes
0 answers
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characteristic ideal of the Iwasawa module

Let $H$ be a complex biquadratic Galois extension of $\mathbb{Q}$ such that the galois group of $H$ is isomorphic to the Klein Group. Let $H_{\infty}$ be an anticyclotomic $\mathbb{Z}_p$-extension of $...
Adel BETINA's user avatar
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3 votes
0 answers
147 views

Iwasawa lambda Invariant for CM type fields

In the following I will follow the notations as in Chapter $11$, section $3$ of the book 'Cohomology of number fields' by Neukirch and others. Let $k_{\infty}$ be a $\mathbb{Z}_p$-extension of a ...
MathStudent's user avatar
3 votes
0 answers
122 views

How to compute group homology of Iwasawa algebra

Let $G$ be a $p$-adic Lie group, $H$ a subgroup of $G$. What is $H_1(H,\Lambda(G))$, where $\Lambda(G)$ is the Iwasawa algebra of $G$ over $\mathbb Z_p$? If it simplies the question, we may assume $G$...
user119481's user avatar
2 votes
1 answer
270 views

On Iwasawa theory of elliptic curves in $\mathrm{PGL}_2(\mathbb{Z}_p)$-extension

Let $E$ be an elliptic curve over the rationals $\mathbb{Q}$. We consider the Galois representation attached to $E$ by acting on its $p$-adic Tate module $T_p(E)$, $$ \rho_E: G_{K} \rightarrow \mathrm{...
Hetong Xu's user avatar
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2 votes
0 answers
155 views

Maximal p-extension and pro-p extension

I’m studying Iwasawa theory and I meet some questions Thanks a lot for your help. Q_1: About terminology $p$-extension. I find many reference use maximal $p$-extension or maximal abelian p-extension ...
Rellw's user avatar
  • 21
2 votes
0 answers
88 views

Compositum of field extensions in context of $\mathbb Z_p$ extension

I had asked this question on stackexchange and I think it is better suited for this site. Suppose I have a $\Gamma \simeq \mathbb Z_p $ extension $F_\infty /F$ of a number field $F$. Let $F_n$ be the ...
mathemather's user avatar
2 votes
0 answers
81 views

Question about infinitude of $m$-irregular primes

Let $p>2$ be a prime, $\zeta$ a primitive $p$th root of unity, and $m >0$ a square-free integer such that $m \not\equiv 3 \mod 4$ and $\gcd(m,p)=1$. Let $\chi$ be the imaginary quadratic ...
matt stokes's user avatar
2 votes
0 answers
147 views

Has there been much research on the Iwasawa theory of bi-quadratic fields?

The simplest non-trivial example of $\mathbb{Z}_p$-extensions happen over imaginary quadratic fields and I've seen a good amount of research done here (from my understanding still a lot to learn). I ...
matt stokes's user avatar
2 votes
0 answers
121 views

Iwasawa theory over function fields - How do eigenvalues vary in $\mathbb Z_\ell$ towers?

Consider a tower of curves $\dots \to C_n \to C_{n-1} \dots \to C_1$ over $\mathbb F_q$ where $C_n: f(x^{\ell^n},y) = 0$.We can look at the multiset $S_n$ of eigenvalues of the Frobenius $\sigma_q$ on ...
Asvin's user avatar
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2 votes
0 answers
110 views

Iwasawa's results about relation between Galois cohomology and principal factorization

Let $K$ be a Galois number field with Galois group and units group $G$ and $U$, respectively. How we can relate the first cohomology group $H^1(G,U)$ to principal factorization in K? I'd try to find ...
A. Maarefparvar's user avatar
2 votes
0 answers
255 views

Merel's theorem on uniform bound for torsion of all elliptic curves

I am reading Silverman's book on Arithmetic of elliptic curves. There he mentions a theorem of Merel (Thm 7.5.1) which reads like this. Thm: For every integer $d \geq 1$, there is a constant $N(d)$ ...
user100603's user avatar
2 votes
0 answers
201 views

Tate module of elliptic curves; Commuting Hom functor and tensor product in the second coordinate

Let $\Lambda$ be the Iwasawa Algebra of the Galois group of the cyclotomic $\mathbb{Z}_p$-extension $\mathbb{Q}_{cyc}$ of $\mathbb{Q}$. Let $\widehat{\Lambda}$ be its Pontryagin dual (i.e the ...
user100603's user avatar
2 votes
0 answers
91 views

Elementary Iwasawa module

Let $k$ be a given number field. What is the importance and applications of knowing that the Iwasawa module $X_\infty$ of $k$ is an elementary $\Lambda$-module?
dekster's user avatar
  • 21
2 votes
0 answers
163 views

$p$-primary torsion of an elliptic curve in the cyclotomic $\mathbb{Z}_p$-extension of a $p$-adic field

Let $K$ be a number field and $v$ be a fixed prime above $p$. Let $k=K_v$. We have the cyclotomic $\mathbb{Z}_p$ extension $K_\infty/K$ and if $w$ is a prime above $v$ in $K_\infty$ we write $k_\infty=...
debanjana's user avatar
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2 votes
0 answers
81 views

An issue with showing that an Iwasawa module has zero $\mu$ invariant

Let $\chi$ denote the $p$-adic cyclotomic character. Let $\mathbb{Q}^{cyc}$ denote the cyclotomic $\mathbb{Z}_p$-extension of $\mathbb{Q}$. Let $\gamma$ be the topological generator of $\Gamma=\text{...
user avatar
2 votes
0 answers
111 views

What is the current status on the corank conjecture for Selmer groups (2)?

This is a follow up to What is the current status on the corank conjecture for Selmer groups? Let E be an elliptic curve over a number field $K$ an imaginary quadratic field in which a prime $p$ ...
user avatar
2 votes
0 answers
132 views

Iwasawa Theoretic Interest in a certain type of result

This question is probably going to sound vague (since it does to me) and I wish I could make it more precise, but here goes. For $p\in \{107, 139, 271,379\}$ Ohtani and Blondeau (in separate papers) ...
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