On codimensions k immersions of m-manifolds for k = 1 and k = m − 2

Let us consider M a closed smooth connected m-manifold, N a smooth (2m − 2)-manifold and a continuous map, with . We prove that if is injective, then f is homotopic to an immersion. Also we give conditions to a map between manifolds of codimension one to be homotopic to an immersion. This work complements some results of Biasi et al. (Manu. Math. 104, 97–110, 2001; Koschorke in The singularity method and immersions of m-manifolds into manifolds of dimensions 2m − 2, 2m − 3 and 2m − 4. Lecture Notes in Mathematics, vol. 1350. Springer, Heidelberg, 1988; Li and Li in Math. Proc. Camb. Phil. Soc. 112, 281–285, 1992).     

Polynomial behavior of special values of partial zeta functions of real quadratic fields at s = 0

We compute the special values of partial zeta functions at s = 0 for family of real quadratic fields K _n and ray class ideals ${\mathfrak{b}_n}$ such that ${\mathfrak{b}_n^{-1} = [1, \delta(n)]}$ where the continued fraction expansion of δ(n) ? 1 is purely periodic and terms are polynomials in n of degree bounded by d. With additional assumptions, we prove that the special values of the partial zeta functions at s = 0 are given by a quasi-polynomial of degree less than or equal to d as a function of n. We apply this to conclude that the special values of the Hecke’s L-functions at s = 0 for the family ${(K_n, \mathfrak{b}_n, \chi_n:= \chi \circ N_{K_n/\mathbb{Q}})}$ for any Dirichlet character χ behave like quasi-polynomial as well. We compute explicitly the coefficients of the quasi-polynomials. Two examples satisfying the condition are presented, and for these two families, the special values of the partial zeta functions at s = 0 are given.     

Axiomatic Aspects of N = 2 Vertex Superalgebras with Odd Formal Variables

We formulate the notion of “N = 2 vertex superalgebra with two odd formal variables” using a Jacobi identity with odd formal variables in which an N = 2 superconformal shift is incorporated into the usual Jacobi identity for a vertex superalgebra. It is shown that as a consequence of these axioms, the N = 2 vertex superalgebra is naturally a representation of the Lie superalgebra isomorphic to the three-dimensional algebra of superderivations with basis consisting of the usual conformal operator and the two N = 2 superconformal operators. In addition, this superconformal shift in the Jacobi identity dictates the form of the odd formal variable components of the vertex operators, and allows one to easily derive the useful formulas in the theory. The notion of N = 2 Neveu–Schwarz vertex operator superalgebra with two odd formal variables is introduced, and consequences of this notion are derived. In particular, we develop the duality properties which are necessary for a rigorous treatment of the correspondence with the underlying supergeometry. Various other formulations of the notion of N = 2 (Neveu–Schwarz) vertex (operator) superalgebra appearing in the mathematics and physics literature are discussed, and several mistakes in the literature are noted and corrected.     

The Automorphism Group Functor of the N = 4 Lie Conformal Superalgebra

In this article, we study the structure and representability of the automorphism group functor of the N = 4 Lie conformal superalgebra over an algebraically closed field k of characteristic zero.     

Decomposition Numbers and Cartan Invariants of S p(4,q), q = 2 n,for p = 2*

Let G be the 4-dimensional sympletic group on a finite field of q elements, q a power of 2. We find all the decomposition numbers of G in characteristic 2, corresponding to the unipotent characters of G. We also find some of the Cartan invariants of G for p = 2.     

On deformation rings of residually reducible Galois representations and R = T theorems

We introduce a new method of proof for R = T theorems in the residually reducible case. We study the crystalline universal deformation ring R (and its ideal of reducibility I) of a mod p Galois representation ρ ₀ of dimension n whose semisimplification is the direct sum of two absolutely irreducible mutually non-isomorphic constituents ρ ₁ and ρ ₂. Under some assumptions on Selmer groups associated with ρ ₁ and ρ ₂ we show that R/I is cyclic and often finite. Using ideas and results of (but somewhat different assumptions from) Bellaïche and Chenevier we prove that I is principal for essentially self-dual representations and deduce statements about the structure of R. Using a new commutative algebra criterion we show that given enough information on the Hecke side one gets an R = T-theorem. We then apply the technique to modularity problems for 2-dimensional representations over an imaginary quadratic field and a 4-dimensional representation over Q.     

Solvability of a Commutative Algebra which Satisfies (x 2)2 = 0

We studied the solvability of the algebra which satisfies the polynomial identity (x ²)² = 0. We believe that, if A is a finite dimensional commutative algebra over a field F of characteristic not 2 which satisfies (x ²)² = 0 for all x ∈ A, then A is solvable. In this article we proved this when dim  _F A ≤ 7.     

The Structure of the Set of Extremal Solutions of Ill-Posed Operator Equation Tx = y with codim R(T) = 1

In this paper, we study the problem of the ill-posed operator equation Tx = y with codim R(T) = 1 in normed linear spaces. The structure of the set of extremal solutions of the equation has been obtained by the maximal elements of the ones in N(T?) and the generalized inverse T ⁺ of T. Furthermore, the representation of the set of the extremal solutions of the equation is given formally.     

Structures of the twisted N = 1 Schrödinger–Neveu–Schwarz algebra

In this paper, we determine the universal central extension, derivation algebra and automorphism group of the twisted N = 1 Schrödinger–Neveu–Schwarz algebra. Furthermore, we generalize these results to the generalized twisted N = 1 Schrödinger–Neveu–Schwarz algebra in the final section.     

Classification of indecomposable modules of the intermediate series over the twisted N = 1 Schrödinger–Neveu–Schwarz algebra

In this paper, a classification of indecomposable modules of the intermediate series over the twisted N = 1 Schrödinger–Neveu–Schwarz algebra is obtained.     

Left-symmetric superalgebra structures on the N = 2 superconformal algebras

The super-Virasoro algebras, also known as the superconformal algebras, are nontrivial graded extensions of the Virasoro algebra to Lie superalgebra version. In this paper, we classify the compatible left-symmetric superalgebra structures on the N = 2 Ramond and Neveu–Schwarz superconformal algebras under certain conditions, which generalizes the corresponding results for the Witt, Virasoro and super Virasoro algebras.     

The Ω Deformed B-model for Rigid N = 2 Theories

We give an interpretation of the Ω deformed B-model that leads naturally to the generalized holomorphic anomaly equations. Direct integration of the latter calculates topological amplitudes of four-dimensional rigid N = 2 theories explicitly in general Ω-backgrounds in terms of modular forms. These amplitudes encode the refined BPS spectrum as well as new gravitational couplings in the effective action of N = 2 supersymmetric theories. The rigid N = 2 field theories we focus on are the conformal rank one N = 2 Seiberg–Witten theories. The failure of holomorphicity is milder in the conformal cases, but fixing the holomorphic ambiguity is only possible upon mass deformation. Our formalism applies irrespectively of whether a Lagrangian formulation exists. In the class of rigid N = 2 theories arising from compactifications on local Calabi–Yau manifolds, we consider the theory of local ${\mathbb{P}^2}$ . We calculate motivic Donaldson–Thomas invariants for this geometry and make predictions for generalized Gromov–Witten invariants at the orbifold point.     

Relatively Free Algebras with the Identity x 3 = 0 #

A basis for a relatively free associative algebra with the identity x ³ = 0 over a field of an arbitrary characteristic is found. As an application, a minimal generating system for the 3 × 3 matrix invariant algebra is determined.     

Equalities and inequalities for Hermitian solutions and Hermitian definite solutions of the two matrix equations AX = B and AXA * = B

This paper studies algebraic properties of Hermitian solutions and Hermitian definite solutions of the two types of matrix equations AX = B and AXA ^* = B. We first establish a variety of rank and inertia formulas for calculating the maximal and minimal ranks and inertias of Hermitian solutions and Hermitian definite solutions of the matrix equations AX = B and AXA ^* = B, and then use them to characterize many qualities and inequalities for Hermitian solutions and Hermitian definite solutions of the two matrix equations and their variations.     

The generalised Fermat equation x 2 + y 3 = z 15

We determine the set of primitive integral solutions to the generalised Fermat equation x ² + y ³ = z ¹⁵. As expected, the only solutions are the trivial ones with xyz = 0 and the non-trivial one (x, y, z) = (± 3, ?2, 1).     

On optimal Hölder regularity of solutions to the equation Δu + b ⋅ ∇u = 0 in two dimensions

We show that for an $L^2$ drift b in two dimensions, if the Hardy norm of $\text{div}b$ is small, then the weak solutions to $\mathrm{\Delta }u+b?\mathrm{?}u=0$ have the same optimal Hölder regularity as in the case of divergence-free drift, that is, $u\in C_{\text{loc}}^{\alpha }$ for all $\alpha \in (0,1)$.     

On the Matrix Equation X = Q − S∗X†S

The positive semidefinite solutions of the nonlinear matrix equation X + S? X?S = Q are investigated. We consider an iterative method converges to a positive semidefinite solution of this equation under the condition Ker X ? Ker S?. The new results are illustrated by numerical examples.     

The Hausdorff-Young theorem for the matricial groups G nm = ax + b

Let G_nm = {ax + b} be the matricial group of a local field. The Hausdorff-Young theorem for G₁₁ was proved by Eymard-Terp [3] in 1978. We will establish here the Hausdorff-Young theorem for G_nm for all . Received: 30 November 2005