# l-functions of siegel modular forms, their families and ...panchish/talkoberw200710.pdf · l...

of 33 /33

Author: others

Post on 28-Jun-2020

0 views

Category:

## Documents

Embed Size (px)

TRANSCRIPT L-Functions of Siegel Modular Forms, Their Familiesand Lifting Conjectures

Alexei PANCHISHKINInstitut Fourier, Université Grenoble-1

B.P.74, 38402 St.�Martin d'Hères, FRANCE

A talk for the Conference "Modulformen"October 29 to November 2, 2007 (Oberwolfach, Germany)

October 2007

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 1 / 27 Introduction

1) L- functions of Siegel modular forms

2) Motivic L-functions for Spg , and their analytic properties

3) Critical values and p-adic constructions for the spinor L-functions

4) A lifting from GSp 2m × GSp 2m to GSp 4m (of genus g = 4m)

5) Constructions of p-adic families of Siegel modular forms

Let Γ = Spg (Z) ⊂ SL2g (Z) be the Siegel modular group of genus g . Let pbe a prime, T(p) = T(1, · · · , 1︸ ︷︷ ︸

g

, p, · · · , p︸ ︷︷ ︸g

) the Hecke p-operator, and

[p]g = pI2g = T(p, · · · , p︸ ︷︷ ︸2g

) the scalar Hecke operator for Spg .

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 2 / 27 The Fourier expansion of a Siegel modular form.

Let f =∑T∈Bn

a(T)qT ∈ Mnk be a Siegel modular form of weight k and of

genus n on the Siegel upper-half plane Hn = {z ∈ Mn(C) | Im(z) > 0}.

The formal Fourier expansion of f uses the symbol

qT = exp(2πi tr(Tz)) =n∏

i=1

qTii

ii

∏i<j

q2Tij

ij

∈ C[[q11, . . . , qnn]][qij , q−1ij ]i ,j=1,··· ,m, where qij = exp(2π(

√−1zi ,j)), and T

is in the semi-group Bn = {T = tT ≥ 0|T half-integral}.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 3 / 27 Satake parameters of an eigenfunction of Hecke operators

Suppose that f ∈ Mnk an eigenfunction of all Hecke operators f 7−→ f |T ,

T ∈ Ln,p for all primes p, hence f |T = λf (T )f .Then all the numbers λf (T ) ∈ C de�ne a homomorphism λf : Ln,p −→ Cgiven by a (n + 1)-tuple of complex numbers (α0, α1, · · · , αn) = (C×)n+1

(the Satake parameters of f ): λf (T ) = Satake(T ) forx0 := α0, . . . , xn := αn, where Satake : Lp,n → Q[x±0 , x

±1 , . . . , x

±n ]Wn is the

Satake isomorphismRecall that

α20α1 · · ·αn = pkn−n(n+1)/2.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 4 / 27 L-functions, functional equation and motives for Spn(see

[Pa94], [Yosh01])

One de�nes

Qf ,p(X ) = (1− α0X )n∏

r=1

∏1≤i1<···<ir≤n

(1− α0αi1 · · ·αirX ),

Rf ,p(X ) = (1− X )n∏

i=1

(1− α−1i X )(1− αiX ) ∈ Q[α±10 , · · · , α±1n ][X ].

Then the spinor L-function L(Sp(f ), s) and the standard L-functionL(St(f ), s, χ) of f (for s ∈ C, and for all Dirichlet characters) χ arede�ned as the Euler products

L(Sp(f ), s, χ) =∏p

Qf ,p(χ(p)p−s)−1

L(St(f ), s, χ) =∏p

Rf ,p(χ(p)p−s)−1

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 5 / 27 Relations with L-functions and motives for Spn

Following [Pa94] and [Yosh01], these functions are conjectured to be motivicfor all k > n:

L(Sp(f ), s, χ) = L(M(Sp(f ))(χ), s), L(St(f ), s) = L(M(St(f ))(χ), s), where

and the motives M(Sp(f )) and M(St(f )) are pure if f is a genuine cusp form(not coming from a lifting of a smaller genus):

M(Sp(f )) is a motive over Q with coe�cients in Q(λf (n))n∈N of rank 2n,of weight w = kn − n(n + 1)/2, and of Hodge type ⊕p,qHp,q, with

p = (k − i1) + (k − i2) + · · ·+ (k − ir ), (3.1)

q = (k − j1) + (k − j2) + · · ·+ (k − is), where r + s = n,

1 ≤ i1 < i2 < · · · < ir ≤ n, 1 ≤ j1 < j2 < · · · < js ≤ n,

{i1, · · · , ir} ∪ {j1, · · · , is} = {1, 2, · · · , n};

M(St(f )) is a motive over Q with coe�cients in Q(λf (n))n∈N of rank2n + 1, of weight w = 0, and of Hodge typeH0,0 ⊕n

i=1 (H−k+i ,k−i ⊕ Hk−i ,−k+i ).

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 6 / 27 A functional equationFollowing general Deligne's conjecture [De79] on the motivic L-functions, theL-function satisfy a functional equation determined by the Hodge structure of amotive:

Λ(Sp(f ), kn − n(n + 1)/2 + 1− s) = ε(f )Λ(Sp(f ), s), where

Λ(Sp(f ), s) = Γn,k(s)L(Sp(f ), s), ε(f ) = (−1)k2n−2 ,

Γ1,k(s) = ΓC(s) = 2(2π)−sΓ(s), Γ2,k(s) = ΓC(s)ΓC(s − k + 2), andΓn,k(s) =

∏p<q ΓC(s − p)hp,qΓR(s − (w/2))a+ΓR(s + 1− (w/2))a− for some

non-negative integers a+ and a−, with a+ + a− = hw/2,w/2, andΓR(s) = π−s/2Γ(s/2), where hp,q = dimCHp,q.In particular, for n = 3 and k ≥ 5, Λ(Sp(f ), s) = Λ(Sp(f ), 3k − 5− s),

Λ(Sp(f ), s) = ΓC(s)ΓC(s − k + 3)ΓC(s − k + 2)ΓC(s − k + 1)L(Sp(f ), s).

For k ≥ 5 the critical values in the sense of Deligne [De79] are :

s = k , · · · , 2k − 5.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 7 / 27 A study of the analytic properties of L(Sp(f ), s)(compare with [Vo]).One could try to use a link between the eigenvalues λf (T ) and the Fouriercoe�cients af (T), where T ∈ D(Γ, S) runs through the Hecke operators, andT ∈ Bn runs over half-integral symmetric matrices.

D(X ) =∞∑

δ=0

T(pδ)X δ =E (X )

F (X ),

where

E (X )

= 1− p2(T2(p

2) + (p2 − p + 1)(p2 + p + 1)[p]3)X 2 + (p + 1)p4T(p)[p]3X

3

− p7[p]3(T2(p

2) + (p2 − p + 1)(p2 + p + 1)[p]3)X 4 + p15[p]33 X

6 ∈ LZ[X ].

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 8 / 27 Computing a formal Dirichlet series

Knowing E (X ), one computes the following formal Dirichlet series

DE (s) =∞∑h=1

TE (h)h−s =∏p

DE ,p(p−s), where

DE ,p(X ) =∞∑

δ=0

TE (pδ)X δ =Dp(X )

E (X )=

1F (X )

∈ D(Γ, S)[[X ]].

Hence, L(Sp(f ), s) =∑∞

h=1 λf (TE )(h)h−s .

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 9 / 27 Main identity

For all T one obtains the following identity

af (T)L(Sp(f ), s) =∞∑h=1

af (T,E , h)h−s , where

f |TE (h) =∑T∈Bn

af (T,E , h)qT.

Such an identity is an unavoidable step in the problem of analyticcontinuation of L(Sp(f ), s) and in the study of its arithmetical implications:one obtains a mean of computing special values out of Fourier coe�cients.We hope also to use the Jacobi forms for the study of L-functionsL(Sp(f ), s).For the standard L(St(f ), s), (see [Pa94], [CourPa], and [Boe-Schm]).

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 10 / 27 Critical values, periods and p-adic L-functions for Sp3A general conjecture by Coates, Perrin-Riou (see [Co-PeRi], [Co], [Pa94]), predictsthat for n = 3 and k > 5, the motivic function L(Sp(f ), s), admits a p-adicanalogue.

The known conjectural condition for the existence of bounded p-adicL-functions in this case takes the form ordp(α0(p)) = 0.Recall : this condition says that for a motive M of rank d,Newton p-Polygone at (d/2)=Hodge Polygone at (d/2)Otherwise, one obtains p-adic L-functions of logarithmic growth o(logh(·))with h = [2ordp(α0(p))] + 1, 2ordp(α0(p)) =the di�erence

Newton p-Polygone at (d/2)�Hodge Polygone at (d/2)

For the unitary groups, this condition for the existence of p-adicL-functions was discussed in [Ha-Li-Sk].

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 11 / 27 Motive of the Rankin product of genus n = 2Let f and g be two Siegel cusp eigenforms of weights k and l , k > l , and letM(Sp(f )) and M(Sp(g)) be the spinor motives of f and g . Then M(Sp(f )) isa motive over Q with coe�cients in Q(λf (n))n∈N of rank 4, of weightw = 2k − 3, and of Hodge type H0,2k−3⊕Hk−2,k−1⊕Hk−1,k−2⊕H2k−3,0, andM(Sp(g)) is a motive over Q with coe�cients in Q(λg (n))n∈N of rank 4, ofweight w = 2l − 3, and of Hodge type H0,2l−3⊕H l−2,l−1⊕H l−1,l−2⊕H2l−3,0.The tensor product M(Sp(f ))⊗M(Sp(g)) is a motive over Q with coe�cientsin Q(λf (n), λg (n))n∈N of rank 16, of weight w = 2k + 2l − 6, and of Hodgetype

H0,2k+2l−6 ⊕ H l−2,2k+l−4 ⊕ H l−1,2k+l−5 ⊕ H2l−3,2k−3

Hk−2,k+2l−4 ⊕ Hk+l−4,k+l−2 ⊕ Hk+l−3,k+l−3+ ⊕ Hk+2l−5,k−1

Hk−1,k+2l−5 ⊕ Hk+l−3,k+l−3− ⊕ Hk+l−2,k+l−4 ⊕ Hk+2l−4,k−2

H2k−3,2l−3 ⊕ H2k+l−5,l−1 ⊕ H2k+l−4,l−2 ⊕ H2k+2l−6,0.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 12 / 27 Motivic L-functions: analytic propertiesFollowing Deligne's conjecture [De79] on motivic L-functions, applied for a Siegel cuspeigenform F for the Siegel modular group Sp4(Z) of genus n = 4 and of weight k > 5,one has Λ(Sp(F ), s) = Λ(Sp(F ), 4k − 9− s), where

Λ(Sp(F ), s) = ΓC(s)ΓC(s − k + 4)ΓC(s − k + 3)ΓC(s − k + 2)ΓC(s − k + 1)

× ΓC(s − 2k + 7)ΓC(s − 2k + 6)ΓC(s − 2k + 5)L(Sp(F ), s),

(compare this functional equation with that given in [An74], p.115).

On the other hand, for m = 2 and for two cusp eigenforms f and g for Sp2(Z) ofweights k , l , k > l + 1, Λ(Sp(f )⊗ Sp(g), s) = ε(f , g)Λ(Sp(f )⊗ Sp(g), 2k + 2l − 5− s),|ε(f , g)| = 1, where

Λ(Sp(f )⊗ Sp(g), s) = ΓC(s)ΓC(s − l + 2)ΓC(s − l + 1)ΓC(s − k + 2)

× ΓC(s − k + 1)ΓC(s − 2l + 3)ΓC(s − k − l + 2)ΓC(s − k − l + 3)

× L(Sp(f )⊗ Sp(g), s).

We used here the Gauss duplication formula ΓC(s) = ΓR(s)ΓR(s + 1).Notice that a+ = a− = 1 in this case, and the conjectural motiveM(Sp(f ))⊗M(Sp(g)) does not admit critical values.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 13 / 27 A holomorphic lifting from GSp2m × GSp2m to GSp4m: aconjectureConjecture (on a lifting from GSp 2m × GSp 2m to GSp 4m)

Let f and g be two Siegel modular forms of genus 2m and of weights k > 2m andl = k − 2m. Then there exists a Siegel modular form F of genus 4m and of weight k with theSatake parameters γ0 = α0β0, γ1 = α1, γ2 = α2, · · · , γ2m = α2m, γ2m+1 = β1, · · · , γ4m = β2mfor suitable choices α0, α1, · · · , α2m and β0, β1, · · · , β2m of Satake's parameters of f and g.One readily checks that the Hodge types of M(Sp(f ))⊗M(Sp(g)) and M(Sp(F )) are thesame (of rank 24m) (it follows from the above description (3.1), and from Künneth's-typeformulas).

An evidence for this version of the conjecture comes from Ikeda-Miyawakiconstructions ([Ike01], [Ike06], [Mur02]): let k be an even positive integer,h ∈ S2k(Γ1) a normalized Hecke eigenform of weight 2k ,g := F2n(h) ∈ Sk+n(Γ2n) the Ikeda�Duke-Imamoglu lift of h of genus 2n(we assume k ≡ n mod 2, n ∈ N).

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 14 / 27 Next let f ∈ Sk+n+r (Γr ) be an arbitrary Siegel cusp eigenform of genus r andweight k + n + r , with n, r ≥ 1.Let us consider the lift F2n+2r (h) ∈ Sk+n+r (Γ2n+2r ), and the integral

Fh,f =

∫Γr\Hr

F2n+2r (h)

((z

z ′

))f (z ′)(det Im(z′)

k+n+r−1dz ′ ∈ Sk+n+r (Γ2n+r ),

which de�nes the Ikeda�Miyawaki lift, where z ∈ H2n+r , z ′ ∈ Hr .Under the non-vanishing condition on Fh,f , one has the equality

L(s,Fh,f , St) = L(s, f , St)2n∏i=1

L(s + k + n + r − i , h)

If we take n = m, r = 2m, k + n + r := k + 3m, then an example of thevalidity of this version of the conjecture is given by

(f , g) = (f ,F2m(h)) 7→ Fh,f ∈ Sk+3m(Γ4m),

(f , g) = (f ,F2m(h)) ∈ Sk+3m(Γ2m)× Sk+m(Γ2m).

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 15 / 27 Another evidence comes from Siegel-Eiseinstein series

f = E 2mk and g = E 2m

k−2m

of even genus 2m and weights k and k − 2m: we have then

α0 = 1, α1 = pk−2m, · · · , α2m = pk−1,

β0 = 1, β1 = pk−4m, · · · , β2m = pk−2m−1,

then we have that

γ0 = 1, γ1 = pk−4m, · · · , γ2m = pk−1,

are the Satake parameters of the Siegel-Eisenstein series F = E 4mk .

Also, the compatibility of the conjecture with the formation ofKlingen-Eisenstein series was checked after a discussion withProf. Tetsushi ITO (Kyoto University) in Luminy in July 2007.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 16 / 27 Remark

If we compare the L-function of the conjecture (given by the Satake parametersγ0 = α0β0, γ1 = α1, γ2 = α2, · · · , γ2m = α2m, γ2m+1 = β1, · · · , γ4m = β2m for suitablechoices α0, α1, · · · , α2m and β0, β1, · · · , β2m of Satake's parameters of f and g), we seethat it corresponds to the tensor product of spinor L-functions, and is not of the sametype as that of the Yoshida's lifting [Yosh81], which is a certain product of Hecke'sL-functions.

We would like to mention in this context Langlands's functoriality: The denominators ofour L-series belong to local Langlands L-factors (attached to representations ofL-groups). If we consider the homomorphisms

LGSp2m = GSpin(4m + 1) → GL22m ,LGSp4m = GSpin(8m + 1) → GL24m ,

we see that our conjecture is compatible with the homomorphism of L-groups

GL22m × GL22m → GL24m , (g1, g2) 7→ g1 ⊗ g2,GLn(C) = LGLn.

However, it is unclear to us if Langlands's functoriality predicts aholomorphic Siegel modular form as a lift.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 17 / 27 Together with complex parameter s it is possible to use certain p-adicparameters in order to study the L-functions. We can use such parametersas the twist with Dirichlet character on one hand, and the weightparameter in the theory of families of modular forms on the other.In several cases one can compute the values of the automorphic L-functionsL(s, π ⊗ χ, r) related to an automorphic representation π of an algebraicgroup G over a number �eld, and the twists with Dirichlet character χ.A usual tool is to represent these special values as integrals giving bothcomplex-analytic and p-adic-analytic continuation.In this way one can treat the cases G = GL2 ×GL2 ×GL2,G = GL2 ×GSp2m, and probably G = GSp2m ×GSp2m using thedoubling method and its p-adic versions. Computations involve di�erentialoperators acting on modular forms.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 18 / 27 Consider Tate's �eld Cp = Q̂p for prime number p. Let us �x the

embedding Qip↪→ Cp and consider the algebraic numbers as numbers p-adic

over ip. For p-adic family k 7→ fk =∑∞

n=1 an(k)qn ∈ Q[[q]] ⊂ Cp[[q]]Fourier coe�cients an(k) of fk and one of Satake's p-parameters

α(k) := α(1)p (k) are given by the certain p-adic analytic functions

k 7→ an(k) for (n, p) = 1. A typical example of a p-adic family is given bythe Eisenstein series.

an(k) =∑

d |n,(d ,p)=1

dk−1, fk = Ek , α(1)p (k) = 1, α(2)

p (k) = pk−1.

The existence of the p-adic family of cusp forms of positive slope σ > 0was shown by Coleman. We de�ne the slope σ = ordp(α

to be constant in a p-adic neighborhood of weight k). An example forp = 7, f = ∆, k = 12, a7 = τ(7) = −7 · 2392, σ = 1 is given byR. Coleman in [CoPB].

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 19 / 27 Motivation for considering of p-adic families

comes from Birch and Swinnerton-Dyer's conjecture, see [Colm03]. For acusp eigenform f = f2, corresponding to an elliptic curve E by Wiles[Wi95], we consider a family containing f . One can try to approachk = 2, s = 1 from the direction, taking k → 2, instead of s → 1, this leadsto a formula linking the derivative over s at s = 1 of the p-adic L-functionwith the derivative over k at k = 2 of the p-adic analytic function αp(k),

see in [CST98]: L′p,f (1) = Lp(f )Lp,f (1) with Lp(f ) = −2dαp(k)

dk

∣∣k=2

.

The validity of this formula needs the existence of our two variableL-function!In order to construct p-adic L-function of two variables (k, s), the theory ofp-adic integration is used. The H-admissible measures with integer Hrelated to σ, which appear in this construction, are obtained fromH-admissible measures with values in various rings of modular forms, inparticular nearly holomorphic modular forms.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 20 / 27 Nearly holomorphic modular forms and the method ofcanonical projection

Let A be a commutative �eld. There are several p-adic approaches forstudying special values of L-functions using the method of canonicalprojection (see [PaTV]). In this method the special values and modularsymbols are considered as A-linear forms over spaces of modular formswith coe�cients in A. Nearly holomorphic ([ShiAr]) modular forms arecertain formal series

g =∞∑n=0

a(n;R)qn ∈ A[[q]][R]

with the property for A = C, z = x + iy ∈ H, R = (4πy)−1, the seriesconverge to a C∞-modular form over H of given weight k and Dirichletcharacter ψ. The coe�cients a(n;R) are polynomials in A[R] of boundeddegree.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 21 / 27 Triple products familiesgive a recent example of families on the algebraic group of higher rank. This aspect of theproject is studied by S. Böcherer and A. Panchishkin [Boe-Pa2006]. The triple product withDirichlet character χ is de�ned as a complex L-function (Euler product of degree 8)L(f1 ⊗ f2 ⊗ f3, s, χ) =

∏p-N L((f1 ⊗ f2 ⊗ f3)p, χ(p)p−s), where

L((f1 ⊗ f2 ⊗ f3)p,X )−1 = det

(18 − X

(1)p,1 0

0 α(2)p,1

)⊗

(1)p,2 0

0 α(2)p,2

)⊗

(1)p,3 0

0 α(2)p,3

)).

We use the corresponding normalized L-function (see [De79], [Co], [Co-PeRi]) :Λ(f1 ⊗ f2 ⊗ f3, s, χ) = ΓC(s)ΓC(s − k3 + 1)ΓC(s − k2 + 1)ΓC(s − k1 + 1)L(f1 ⊗ f2 ⊗ f3, s, χ),where ΓC(s) = 2(2π)−sΓ(s). The Gamma-factor determines the critical valuess = k1, . . . , k2 + k3 − 2 of Λ(s), which we explicitly evaluate (like in the classical formulaζ(2) = π2

6 ). A functional equation of Λ(s) has the form: s 7→ k1 + k2 + k3 − 2− s.Let us consider the product of three eigenvalues:λ = λ(k1, k2, k3) = α

(1)p,1(k1)α

(1)p,2(k2)α

(1)p,3(k3) with the slope

σ = vp(λ(k1, k2, k3)) = σ(k1, k2, k3) = σ1 + σ2 + σ3 constant and positivefor all triplets (k1, k2, k3) in an appropriate p-adic neighbourhood of the�xed triplet of weights (k1, k2, k3).

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 22 / 27 The statement of the problem

for triple products is following: given three p-adic analytic families fj ofslope σj ≥ 0, to construct a four-variable p-adic L-function attached toGarrett's triple product of these families. We show that this functioninterpolates the special values (s, k1, k2, k2) 7−→ Λ(f1,k1 ⊗ f2,k2 ⊗ f3,k3 , s, χ)at critical points s = k1, . . . , k2 + k3 − 2 for balanced weightsk1 ≤ k2 + k3 − 2; we prove that these values are algebraic numbers afterdividing by certain �periods�. However the construction uses directlymodular forms, and not the L-values in question, and a comparison ofspecial values of two functions is done after the construction.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 23 / 27 Main result for triple products1) The function Lf : (s, k1, k2, k3) 7→ 〈f0,E(−r ,χ)〉

on four variables(χ · y rp , k1, k2, k3) ∈ X ×B1 ×B2 ×B3;

2) Comparison of complex and p-adic values: for all (k1, k2, k3) in an a�noidneighborhoodB = B1 ×B2 ×B3 ⊂ X 3, satisfying k1 ≤ k2 + k3 − 2: the values ats = k2 + k3 − 2− rcoincide with the normalized critical special values

L∗(f1,k1 ⊗ f2,k2 ⊗ f3,k3 , k2 + k3 − 2− r , χ) (r = 0, . . . , k2 + k3 − k1 − 2) ,

for Dirichlet characters χ mod Npv , v ≥ 1.3) Dependence on x ∈ X : let H = [2ordp(λ)] + 1. For any �xed

(k1, k2, k3) ∈ B and x = χ · y rp then the following linear form (representingmodular symbols for triple modular forms)

x 7−→

⟨f0,E(−r , χ)

⟩⟨f0, f0

⟩,

extends to a p-adic analytic function of type o(logH(·)) of the variablex ∈ X .

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 24 / 27 A general programWe plan to extend this construction to other sutuations as follows :

1) Construction of modular distributions Φj with values in an in�nite dimensionalmodular tower M(ψ).

2) Application of a canonical projector of type πα onto a �nite dimensional subspaceMα(ψ) of Mα(ψ).

3) General admissibility criterium. The family of distributions πα(Φj) with value inMα(ψ) give a h-admissible measure Φ̃ with value in the moduli of �nite rank.

4) Application of a linear form ` of type of a modular symbol produces distributionsµj = `(πα(Φj)), and an admissible measure from congruences between modularforms πα(Φj).

5) One shows that certain integrals µj(χ) of the distributions µj coincide with certainL-values; however, these integrals are not necessary for the construction of measures(already done at stage 4).

6) One shows a result of uniqueness for the constructed h-admissible measures : theyare determined by many of their integrals over Dirichlet characters (not all).

7) In most cases we can prove a functional equation for the constructed measure µ(using the uniqueness in 6), and using a functional equation for the L-values (overcomplex numbers, computed at stage 5).

This strategy is already applicable in various cases.

Alexei PANCHISHKIN (Grenoble) L-Functions of Siegel Modular Forms Oberwolfach 2007 25 / 27 Bibliography

Andrianov, A.N., Shimura's conjecture for Siegel's modular group ofgenus 3, Dokl. Akad. Nauk SSSR 177 (1967), 755-758 = Soviet Math.Dokl. 8 (1967), 1474-1478.

Andrianov, A.N., Rationality of multiple Hecke series of a completelinear group and Shimura's hypothesis on Hecke's series of a symplecticgroup, Dokl. Akad. Nauk SSSR 183 (1968), 9-11 = Soviet Math. Dokl.9 (1968), 1295 - 1297. MR

Andrianov, A.N., Rationality theorems for Hecke series and zetafunctions of the groups GLn and SPn over local �elds, Izv. Akad. NaukSSSR, Ser. Mat., Tom 33 (1969), No. 3, (Math. USSR � Izvestija, Vol.3 (1969), No. 3, pp. 439�476).

Andrianov, A.N., Spherical functions for GLn over local �elds andsummation of Hecke series, Mat. Sbornik, Tom 83 (125) (1970), No 3,(Math. USSR Sbornik, Vol. 12 (1970), No. 3, pp. 429�452).

27 Andrianov, A.N., Euler products corresponding to Siegel modular formsof genus 2, Russian Math. Surveys, 29:3 (1974), pp. 45�116, (UspekhiMat. Nauk 29:3 (1974) pp. 43�110).

Andrianov, A.N., Quadratic Forms and Hecke Operators,Springer-Verlag, Berlin, Heidelberg, New York, London, Paris, Tokyo,1987.

Andrianov, A.N., Zhuravlev, V.G., Modular Forms and HeckeOperators, Translations of Mathematical Monographs, Vol. 145, AMS,Providence, Rhode Island, 1995.

Böcherer, S., Panchishkin, A.A., Admissible p-adic measures attachedto triple products of elliptic cusp forms, accepted in Documenta Math.in March 2006 (a special volume dedicated to John Coates).

Böcherer, S., and Schmidt, C.-G., p-adic measures attached to Siegelmodular forms, Ann. Inst. Fourier 50, N◦5, 1375-1443 (2000).

Coates, J. On p�adic L�functions. Sem. Bourbaki, 40eme annee,1987-88, n◦ 701, Asterisque (1989) 177�178.

28 Coates, J. and Perrin-Riou, B., On p-adic L-functions attached tomotives over Q, Advanced Studies in Pure Math. 17, 23�54 (1989)

R. Coleman, p-adic Banach spaces and families of modular forms,Invent. Math. 127, N◦ 3 (1997), 417�479.

R. Coleman, G. Stevens, J. Teitelbaum, Numerical experiments onfamilies of p-adic modular forms, in Computational perspectives inNumber Theory, ed. by D.A. Buell, J.T. Teitelbaum, Amer. Math. Soc.(1998), 143�158.

P. Colmez La conjecture de Birch et Swinnerton-Dyer p-adique,Séminaire Bourbaki, exposé n◦ 919, juin 2003.

Courtieu,M., Panchishkin ,A.A., Non-Archimedean L-Functions andArithmetical Siegel Modular Forms, Lecture Notes in Mathematics1471, Springer-Verlag, 2004 (2nd augmented ed.)

Deligne P., Valeurs de fonctions L et périodes d'intégrales,Proc.Sympos.Pure Math. vol. 55. Amer. Math. Soc., Providence, RI,1979 , 313-346

29 Evdokimov, S. A., Dirichlet series, multiple Andrianov zeta-functions inthe theory of Euler modular forms of genus 3, (Russian) Dokl. Akad.Nauk SSSR 277 (1984), no. 1, 25�29.

Hecke, E., Über Modulfunktionen und die Dirichletschen Reihen mitEulerscher Produktenwickelung, I, II. Math. Annalen 114 (1937), 1-28,316-351 (Mathematische Werke. Göttingen: Vandenhoeck undRuprecht, 1959, 644-707).

Harris, M., Li, Jian-Shu., Skinner, Ch.M., p-adic L-functions for unitaryShimura varieties. Preprint, 2006.

Ikeda, T., On the lifting of elliptic cusp forms to Siegel cusp forms ofdegree 2n, Ann. of Math. (2) 154 (2001), 641-681.

Ikeda, T., Pullback of the lifting of elliptic cusp forms and Miyawaki'sConjecture Duke Mathematical Journal, 131, 469-497 (2006)

Kurokawa, Nobushige, Analyticity of Dirichlet series over prime powers.Analytic number theory (Tokyo, 1988), 168�177, Lecture Notes inMath., 1434, Springer, Berlin, 1990.

30 Maass, H. Inde�nite Quadratische Formen und Eulerprodukte. Comm.on Pure and Appl. Math, 19, 689-699 (1976)

Murokawa, K., Relations between symmetric power L-functions andspinor L-functions attached to Ikeda lifts, Kodai Math. J. 25, 61-71(2002)

Panchishkin, A., Admissible Non-Archimedean standard zeta functionsof Siegel modular forms, Proceedings of the Joint AMS SummerConference on Motives, Seattle, July 20�August 2 1991, Seattle,Providence, R.I., 1994, vol.2, 251 � 292

Panchishkin, A.A., A new method of constructing p-adic L-functionsassociated with modular forms, Moscow Mathematical Journal, 2(2002), Number 2, 1-16

Panchishkin, A.A., Two variable p-adic L functions attached toeigenfamilies of positive slope, Invent. Math. v. 154, N3 (2003), pp.551 - 615

31 Panchishkin,A.A., Triple products of Coleman's families and theirperiods (a joint work with S.Boecherer) Proceedings of the 8th Hakubaconference �Periods and related topics from automorphic forms�,September 25 - October 1, 2005

Panchishkin,A.A., p-adic Banach modules of arithmetical modularforms and triple products of Coleman's families, (for a special volumeof Quarterly Journal of Pure and Applied Mathematics dedicated toJean-Pierre Serre), 2006.

Panchishkin, A., Vankov, K. On the numerator of the symplectic Heckeseries of degree three. Arxiv, math.NT/0604602 (2006).

Rhodes, J.A. and Shemanske, T.R. Rationality theorems for Heckeoperators on GLn, J. Number Theory 102 (2003), no. 2, 278-297.

Shimura, G., On modular correspondences for Sp(n, Z) and theircongruence relations, Proc. Nat. Acad. Sci. U.S.A. 49 (1963), 824-828.

Shimura G., Introduction to the Arithmetic Theory of AutomorphicFunctions, Princeton Univ. Press, 1971.

32 G. Shimura, Arithmeticity in the theory of automorphic forms,Mathematical Surveys and Monographs. 82. Providence, RI: AmericanMathematical Society (AMS). x, 302 p. (2000)

Tamagawa T., On the ζ-function of a division algebra, Ann. of Math.77 (1963), 387-405

Tilouine, J. and Urban, E. , Several variable p-adic families ofSiegel-Hilbert cusp eigenforms and their Galois representations, Ann.scient. Éc. Norm. Sup. 4e série, 32 (1999) 499�574.

Vankov, K. Explicit formula for the symplectic Hecke series of genusfour. Arxiv, math.NT/0606492, (2006).

S. Vo, The spin L-function on the symplectic group GSp(6), IsraelJournal of Mathematics 101 (1997), 1-71.

A. Wiles, Modular elliptic curves and Fermat's Last Theorem, Ann.Math., II. Ser. 141, No.3 (1995), 443�55.

Yoshida, H., Siegel's Modular Forms and the Arithmetic of QuadraticForms, Inventiones math. 60, 193�248 (1980)

33 Yoshida, H., Motives and Siegel modular forms, American Journal ofMathematics, 123 (2001), 1171�1197.

34