The representation parabolically induced from an irreducible supercuspidal representation is considered. Irreducible components of Jacquet modules with respect to induction in stages are given. The results are used for consideration of generalized Steinberg representations.

We classify all 3 letter patterns that are avoidable in the abelian sense. A short list of four letter patterns for which abelian avoidance is undecided is given. Using a generalization of Zimin words we deduce some properties of $\omega$-words avoiding these patterns.

We present a new approach to singular reduction of Hamiltonian systems with symmetries. The tools we use are the category of differential spaces of Sikorski and the Stefan-Sussmann theorem. The former is applied to analyze the differential structure of the spaces involved and the latter is used to prove that some of these spaces are smooth manifolds.

Our main result is the identification of accessible sets of the generalized distribution spanned by the Hamiltonian vector fields of invariant functions with singular reduced spaces. We are also able to describe the differential structure of a singular reduced space corresponding to a coadjoint orbit which need not be locally closed.

The proof of Lemma 3.4 in $\left[ \text{F} \right]$ relies on the incorrect equality ${{\mu }_{j}}(AB)={{\mu }_{j}}(BA)$ for singular values (for a counterexample, see [S, p. 4]). Thus, Theorem 3.1 as stated has not been proven. However, with minor changes, we can obtain a bound for the counting function in terms of the growth of the Fourier transform of $\left| V \right|$.

The question of counting minimal factorizations of permutations into transpositions that act transitively on a set has been studied extensively in the geometrical setting of ramified coverings of the sphere and in the algebraic setting of symmetric functions.

It is natural, however, from a combinatorial point of view to ask how such results are affected by counting up to equivalence of factorizations, where two factorizations are equivalent if they differ only by the interchange of adjacent factors that commute. We obtain an explicit and elegant result for the number of such factorizations of permutations with precisely two factors. The approach used is a combinatorial one that rests on two constructions.

We believe that this approach, and the combinatorial primitives that have been developed for the “cut and join” analysis, will also assist with the general case.

We show that the Seiberg-Witten invariants of a lens space determine and are determined by its Casson-Walker invariant and its Reidemeister-Turaev torsion.

Let $\Gamma$ be a torsion free lattice in $G=\text{PGL}\left( 3,\mathbb{F} \right)$ where $\mathbb{F}$ is a nonarchimedean local field. Then $\Gamma$ acts freely on the affine Bruhat-Tits building $B$ of $G$ and there is an induced action on the boundary $\Omega$ of $B$. The crossed product ${{C}^{*}}$ -algebra $\mathcal{A}\left( \Gamma \right)=C\left( \Omega \right)\rtimes \Gamma$ depends only on $\Gamma$ and is classified by its $K$-theory. This article shows how to compute the $K$-theory of $\mathcal{A}\left( \Gamma \right)$ and of the larger class of rank two Cuntz-Krieger algebras.

Let $X$ be a nonsingular algebraic variety in characteristic zero. To an effective divisor on $X$ Kontsevich has associated a certain motivic integral, living in a completion of the Grothendieck ring of algebraic varieties. He used this invariant to show that birational (smooth, projective) Calabi-Yau varieties have the same Hodge numbers. Then Denef and Loeser introduced the invariant motivic (Igusa) zeta function, associated to a regular function on $X$, which specializes to both the classical $p$-adic Igusa zeta function and the topological zeta function, and also to Kontsevich's invariant.

This paper treats a generalization to singular varieties. Batyrev already considered such a ‘Kontsevich invariant’ for log terminal varieties (on the level of Hodge polynomials of varieties instead of in the Grothendieck ring), and previously we introduced a motivic zeta function on normal surface germs. Here on any $\mathbb{Q}$-Gorenstein variety $X$ we associate a motivic zeta function and a ‘Kontsevich invariant’ to effective $\mathbb{Q}$-Cartier divisors on $X$ whose support contains the singular locus of $X$.

Let ${{p}_{w}}(n)$ be the weighted partition function defined by the generating function $\Sigma _{n=0}^{\infty }{{p}_{w}}(n){{x}^{n}}=\prod{_{m=1}^{\infty }{{(1-{{x}^{m}})}^{-w(m)}}}$ , where $w\left( m \right)$ is a non-negative arithmetic function. Let ${{P}_{w}}(u)={{\Sigma }_{n\le u}}{{p}_{w}}(n)\,and\,{{N}_{w}}(u)={{\Sigma }_{n\le u}}w(n)$ be the summatory functions for ${{p}_{w}}(n)$ and $w\left( n \right)$, respectively. Generalizing results of G. A. Freiman and E. E. Kohlbecker, we show that, for a large class of functions $\Phi \left( u \right)$ and $\text{ }\!\!\lambda\!\!\text{ }\left( u \right)$, an estimate for ${{P}_{w}}\left( u \right)$ of the form log ${{P}_{w}}(u)=\Phi (u)\{1+Ou(1/\lambda (u))\}$$\left( u\to \infty \right)$ implies an estimate for ${{N}_{w}}(u)$ of the form ${{N}_{w}}(u)={{\Phi }^{*}}(u)\{1+O(1/\log \lambda (u))\}$$\left( u\to \infty \right)$ with a suitable function ${{\Phi }^{*}}(u)$ defined in terms of $\Phi \left( u \right)$. We apply this result and related results to obtain characterizations of the Riemann Hypothesis and the Generalized Riemann Hypothesis in terms of the asymptotic behavior of certain weighted partition functions.