On the Birch-Swinnerton-Dyer conjecture mod p

The article contains a definition of p-adic height function on the group of $\text{Q}$-points of an elliptic curve and the formula of the mod p variant of the Birch-Swinnerton-Dyer conjecture. Presented are the results of numerical computations which confirm this conjecture in several particular cases.     

On Blattner's formula for the discrete series representations of SO(2n, 1)

Blattner's conjecture gives a formula for the multiplicity with which a unitary irreducible representation of the maximal compact subgroup K appears in any discrete series representation of a semisimple Lie group G. We give an elementary derivation of this formula from Harish Chandra's character formula for G ～- SO_e(2n, 1) (n ? 2). The idea is to regularize the character (on the Cartan subgroup), to show that the regularization is unique, and to derive the multiplicities by expanding the resulting distribution in a Fourier series. To prove uniqueness of the regularization one uses a priori constraints on the multiplicities (=Fourier coefficients) that follow from the subquotient theorem.     

An O(n log n) unidirectional distributed algorithm for extrema finding in a circle

In this paper we present algorithms, which given a circular arrangement of n uniquely numbered processes, determine the maximum number in a distributive manner. We begin with a simple unidirectional algorithm, in which the number of messages passed is bounded by 2 n log n + O(n). By making several improvements to the simple algorithm, we obtain a unidirectional algorithm in which the number of messages passed is bounded by 1.5nlogn + O(n). These algorithms disprove Hirschberg and Sinclair's conjecture that O(n²) is a lower bound on the number of messages passed in undirectional algorithms for this problem. At the end of the paper we indicate how our methods can be used to improve an algorithm due to Peterson, to obtain a unidirectional algorithm using at most 1.356nlogn + O(n) messages. This is the best bound so far on the number of messages passed in both the bidirectional and unidirectional cases.     

Homoclinic tangencies versus uniform hyperbolicity for conservative 3-flows

We prove that a volume-preserving three-dimensional flow can be C¹-approximated by a volume-preserving Anosov flow or else by another volume-preserving flow exhibiting a homoclinic tangency. This proves the conjecture of Palis for conservative 3-flows and with respect to the C¹-topology.     

The validity of the strong perfect-graph conjecture for (K4−e)-free graphs

Berge's strong perfect-graph conjecture states that a graph is perfect iff it has neither C_2n+1 nor $\text{C}{}_{\mathrm{2n+1}}$, n ≥ 2 as an induced subgraph. In this note we establish the validity of this conjecture for (K₄?e)-free graphs.     

Conjectures on tail asymptotics of the marginal stationary distribution for a multidimensional SRBM

We are concerned with the stationary distribution of a d-dimensional semimartingale reflecting Brownian motion on a nonnegative orthant, provided it is stable, and conjecture about the tail decay rate of its marginal distribution in an arbitrary direction. Due to recent studies, the conjecture is true for d=2. We show its validity for the skew symmetric case for a general d.     

Conjectured statistics for the q,t-Catalan numbers

We introduce the distribution function F_n(q,t) of a pair of statistics on Catalan words and conjecture F_n(q,t) equals Garsia and Haiman's q,t-Catalan sequence C_n(q,t), which they defined as a sum of rational functions. We show that F_n,s(q,t), defined as the sum of these statistics restricted to Catalan words ending in s ones, satisfies a recurrence relation. As a corollary we are able to verify that F_n(q,t)=C_n(q,t) when t=1/q. We also show the partial symmetry relation F_n(q,1)=F_n(1,q). By modifying a proof of Haiman of a q-Lagrange inversion formula based on results of Garsia and Gessel, we obtain a q-analogue of the general Lagrange inversion formula which involves Catalan words grouped according to the number of ones at the end of the word.     

Disturbing the Dyson conjecture, in a generally GOOD way

Dyson's celebrated constant term conjecture [F.J. Dyson, Statistical theory of the energy levels of complex systems I, J. Math. Phys. 3 (1962) 140-156] states that the constant term in the expansion of _∏1≦i≠j≦naj(1−xi/xj) is the multinomial coefficient (a₁+a₂+?+an)!/(a₁!a₂!?an!). The definitive proof was given by I.J. Good [I.J. Good, Short proof of a conjecture of Dyson, J. Math. Phys. 11 (1970) 1884]. Later, Andrews extended Dyson's conjecture to a q-analog [G.E. Andrews, Problems and prospects for basic hypergeometric functions, in: R. Askey (Ed.), The Theory and Application of Special Functions, Academic Press, New York, 1975, pp. 191-224]. In this paper, closed form expressions are given for the coefficients of several other terms in the Dyson product, and are proved using an extension of Good's idea. Also, conjectures for the corresponding q-analogs are supplied. Finally, perturbed versions of the q-Dixon summation formula are presented.     

Special values of L-functions of elliptic curves over Q and their base change to real quadratic fields

For an elliptic curve E over Q, and a real quadratic extension F of Q, satisfying suitable hypotheses, we study the algebraic part of certain twisted L-values for E/F. The Birch and Swinnerton-Dyer conjecture predicts that these L-values are squares of rational numbers. We show that this question is related to the ratio of Petersson inner products of a quaternionic form on a definite quaternion algebra over Q and its base change to F.     

An effective isomorphy criterion for mod ? Galois representations

In this paper, we consider mod ? Galois representations of Q. In particular, we develop an effective criterion to decide whether or not two mod ? Galois representations Q are isomorphic. The proof uses methods from Khare-Wintenberger?s recent theorem on Serre?s conjecture along with theorems by Sturm and Kohnen.     

The role of restriction theorems in harmonic analysis on harmonic NA groups

We shall obtain inequalities for Fourier transform via moduli of continuity on NA groups. These results in particular settle the conjecture posed in a recent paper by W.O. Bray and M. Pinsky in the context of noncompact rank one symmetric spaces. These problems naturally demand versions of Fourier restriction theorem on these spaces which we shall prove. We shall also elaborate on the connection between the restriction theorem and the Kunze-Stein phenomena on NA groups. For noncompact Riemannian symmetric spaces of rank one analogues of all the results follow the same way.     

On x3 + y3 = D

The simplest case of Fermat's last theorem, the impossibility of solving x³ + y³ = z³ in nonzero integers, has been proved. In other words, 1 is not expressible as a sum of two cubes of rational numbers. However, the slightly extended problem, in which integers D are expressible as a sum of two cubes of rational numbers, is unsolved. There is the conjecture (based on work of Birch, Swinnerton-Dyer, and Stephens) that x³ + y³ = D is solvable in the rational numbers for all square-free positive integers D ≡ 4 (mod 9). The condition that D should be square-free is necessary. As an example, it is shown near the end of this paper that x³ + y³ = 4 has no solutions in the rational numbers. The remainder of this paper is concerned with the proof published by the first author (Proc. Nat. Acad. Sci. USA., 1963) entitled “Remarks on a conjecture of C. L. Siegel.” This pointed out an error in a statement of Siegel that the diophantine equation ax³ + bx²y + cxy² + dy³ = n has a bounded number of integer solutions for fixed a, b, c, d, and, further, that the bound is independent of a, b, c, d, and n. However, x³ + y³ = n already has an unbounded number of solutions. The paper of S. Chowla itself contains an error or at least an omission. This can be rectified by quoting a theorem of E. Lutz.     

Isomorphism Conjecture for homotopy K-theory and groups acting on trees

We discuss an analogon to the Farrell-Jones Conjecture for homotopy algebraic K-theory. In particular, we prove that if a group G acts on a tree and all isotropy groups satisfy this conjecture, then G satisfies this conjecture. This result can be used to get rational injectivity results for the assembly map in the Farrell-Jones Conjecture in algebraic K-theory.     

On 2-factors with k components

In this paper we study the minimum degree condition for a Hamiltonian graph to have a 2-factor with k components. By proving a conjecture of Faudree et al. [A note on 2-factors with two components, Discrete Math. 300 (2005) 218-224] we show the following. There exists a real number ε>0 such that for every integer k?2 there exists an integer n₀=n₀(k) such that every Hamiltonian graph G of order n?n₀ with has a 2-factor with k components.     

A proof of the q,t-Catalan positivity conjecture

We present here a proof that a certain rational function C_n(q,t) which has come to be known as the “q,t-Catalan” is in fact a polynomial with positive integer coefficients. This has been an open problem since 1994. The precise form of the conjecture is given in Garsia and Haiman (J. Algebraic Combin. 5(3) (1996) 191), where it is further conjectured that C_n(q,t) is the Hilbert series of the diagonal harmonic alternants in the variables (x₁,x₂,…,x_n;y₁,y₂,…,y_n). Since C_n(q,t) evaluates to the Catalan number at t=q=1, it has also been an open problem to find a pair of statistics a(π),b(π) on Dyck paths π in the n×n square yielding C_n(q,t)=∑_πt^a(π)q^b(π). Our proof is based on a recursion for C_n(q,t) suggested by a pair of statistics a(π),b(π) recently proposed by Haglund. Thus, one of the byproducts of our developments is a proof of the validity of Haglund's conjecture. It should also be noted that our arguments rely and expand on the plethystic machinery developed in Bergeron et al. (Methods and Applications of Analysis, Vol. VII(3), 1999, p. 363).     

La conjecture de Baum–Connes à coefficients pour le groupe Sp(n,1)The Baum–Connes conjecture with coefficients for the group Sp(n,1)

We show that the Lie groups Sp(n,1) satisfy the Baum–Connes conjecture with arbitrary coefficients. The main tool is the construction, due to Cowling, of a family of uniformly bounded representations. To cite this article: P. Julg, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 533–538.     

On the diophantine equation x(x + 1)(x + 2)…(x + (m − 1)) =g(y)

Let g(y) ? Q[Y] be an irreducible polynomial of degree n ≥ 3. We prove that there are only finitely many rational numbers x, y with bounded denominator and an integer m ≥ 3 satisfying the equation x(x + 1) (x + 2)…(x + (m − 1) ) = g(y). We also obtain certain finiteness results when g(y) is not an irreducible polynomial.     

The representation type of Hecke algebras of type B

This paper determines the representation type of the Iwahori-Hecke algebras of type B when q≠±1. In particular, we show that a single parameter non-semisimple Iwahori-Hecke algebra of type B has finite representation type if and only if q is a simple root of the Poincaré polynomial, confirming a conjecture of Uno's (J. Algebra 149 (1992) 287).