Narrow Results

Let ℓ > 0 be a square free integer and the ring of integers of the imaginary quadratic field . Codes C over K determine lattices Λ_ℓ(C) over rings . The theta functions θ_Λℓ(C) of such lattices are known to determine the symmetrized weight enumerator swe(C) for small primes p = 2, 3; see [1, 10].

In this paper we explore such constructions for any p. If p ∤ ℓ then the ring is isomorphic to 𝔽_p² or 𝔽_p × 𝔽_p. Given a code C over we define new theta functions on the corresponding lattices. We prove that the theta series θ_Λℓ(C) can be written in terms of the complete weight enumerator of C and that θ_Λℓ(C) is the same for almost all ℓ. Furthermore, for large enough ℓ, there is a unique complete weight enumerator polynomial which corresponds to θ_Λℓ(C).

Based on the study of the dynamics of a dissipation-modified Toda anharmonic (one-dimensional, circular) lattice ring we predict here a new form of electric conduction mediated by dissipative solitons. The electron-ion-like interaction permits the trapping of the electron by soliton excitations in the lattice, thus leading to a soliton-driven current much higher than the Drude-like (linear, Ohmic) current. Besides, as we lower the values of the externally imposed field this new form of current survives, with a field-independent value.

This work provides a description of the main computational tools for the study of discrete breathers. It starts with the observation of breathers through simple numerical runs, the study uses targeted initial conditions, and discrete breather impact on transient processes and thermal equilibrium. We briefly describe a set of numerical methods to obtain breathers up to machine precision. In the final part of this work we apply the discussed methods to study the competing length scales for breathers with purely anharmonic interactions — favoring superexponential localization — and long range interactions, which favor algebraic decay in space. As a result, we observe and explain the presence of three different spatial tail characteristics of the considered localized excitations.

We continue the study of the preradicals of a ring in the lattice point of view. We introduce several interesting preradicals associated to a given preradical and some partitions of the whole lattice in terms of preradicals. As an application, we also give some classification theorems.

This paper presents three main ideas. They are the Metatheorem, the lattice embedding for sets, and the lattice embedding for algebras.

The Metatheorem allows you to convert existing theorems about classical subsets into corresponding theorem about fuzzy subsets. The concept of a fuzzyfiable operation on a powerset is defined. The main result states that any implication or identity which can be stated using fuzzyfiable operations is true about fuzzy subsets if and only if it is true about classical subsets.

The lattice embedding theorem for sets shows that for any set X, there is a set Y such that the lattice of fuzzy subsets of X is isomorphic to a sublattice of the classical subsets of Y. In fact it is further proved that if X is infinite, then we can choose Y = X and get the surprising result that the lattice of fuzzy subsets of X is isomorphic to a sublattice of the classical subsets of X itself. The idea is illustrated with an example explicitly showing how the lattice of fuzzy subsets of the closed unit interval 𝕀 = [0,1] embeds into the lattice of classical subsets of 𝕀.

The lattice embedding theorem for algebras shows that under certain circumstances the lattice of fuzzy subalgebras of an algebra A embeds into the lattice of classical subalgebras of a closely related algebra A′. The following sample use of this embeding theorem is given. It is a well known fact that the lattice of normal subgroups of a group is a modular lattice. The embeding theorem is used here to conclude that lattice of fuzzy normal subgroups of a group is a modular lattice too.

Proxy Re-Encryption (PRE) is a cryptographic primitive that allows a proxy to turn an Alice’s ciphertext into a Bob’s ciphertext on the same plaintext. All of the PRE schemes are public key encryption and semantic security. Deterministic Public Key Encryption (D-PKE) provides an alternative to randomized public key encryption in various scenarios where the latter exhibits inherent drawbacks. In this paper, we construct the first multi-use unidirectional D-PRE scheme from Lattices in the auxiliary-input setting. We also prove that it is PRIV1-INDr secure in the standard model based on the LWR. Finally, an identity-based D-PRE is obtained from the basic construction.

We first summarize features of free, forced and stochastic harmonic oscillations and, following an idea first proposed by Lord Rayleigh in 1883, we discuss the possibility of maintaining them in the presence of dissipation. We describe how phonons appear in a harmonic (linear) lattice and then use the Toda exponential interaction to illustrate solitonic excitations (cnoidal waves) in a one-dimensional nonlinear lattice. We discuss properties such as specific heat (at constant length/volume) and the dynamic structure factor, both over a broad range of temperature values. By considering the interacting Toda particles to be Brownian units capable of pumping energy from a surrounding heat bath taken as a reservoir we show that solitons can be excited and sustained in the presence of dissipation. Thus the original Toda lattice is converted into an active lattice using Lord Rayleigh's method. Finally, by endowing the Toda–Brownian particles with electric charge (i.e. making them positive ions) and adding free electrons to the system we study the electric currents that arise. We show that, following instability of the base linear Ohm(Drude) conduction state, the active electric Toda lattice is able to maintain a form of high-T supercurrent, whose characteristics we then discuss.

At the 2011 Durham Conference "Geometry and Arithmetic of Lattices" M. Kapovich formulated the following

Question. Does there exist an embedding ℤ² * ℤ ↪ SL(3, ℤ)?

The goal of the paper is to prove the following

Main Theorem.If p and m are arbitrary positive integers then there exists an embeddingℤ² * F_m ↪ SL(3, ℤ[1/p]).

Every isometry of a finite-dimensional Euclidean space is a product of reflections and the minimum length of a reflection factorization defines a metric on its full isometry group. In this paper we identify the structure of intervals in this metric space by constructing, for each isometry, an explicit combinatorial model encoding all of its minimum length reflection factorizations. The model is largely independent of the isometry chosen in that it only depends on whether or not some point is fixed and the dimension of the space of directions that points are moved.

In this paper, we carry out in an abstract order context some real subset combinatorial problems. Specifically, let $(X,\le ,c)$ be a finite poset, where $c:X\to X$ is an order-reversing and involutive map such that $c(x)\ne x$ for each $x\in X$. Let $B_2=\{N<P\}$ be the Boolean lattice with two elements and ${{𝒲}}_{+}(X,B_2)$ the family of all the order-preserving 2-valued maps $A:X\to B_2$ such that $A(c(x))=P$ if $A(x)=N$ for all $x\in X$. In this paper, we build a family ${{ℬ}}_{w+}(X)$ of particular subsets of $X$, that we call $w_{+}$-bases on $X$, and we determine a bijection between the family ${{ℬ}}_{w+}(X)$ and the family ${{𝒲}}_{+}(X,B_2)$. In such a bijection, a $w_{+}$-basis $\mathrm{\Omega }$ on $X$ corresponds to a map $A\in {{𝒲}}_{+}(X,B_2)$ whose restriction of $A$ to $\mathrm{\Omega }$ is the smallest 2-valued partial map on $X$ which has $A$ as its unique extension in ${{𝒲}}_{+}(X,B_2)$. Next we show how each $w_{+}$-basis on $X$ becomes, in a particular context, a sub-system of a larger system of linear inequalities, whose compatibility implies the compatibility of the whole system.

We prove the following instance of a conjecture stated in [P. E. Eleftheriou and Y. Peterzil, Definable quotients of locally definable groups, Selecta Math. (N.S.) 18(4) (2012) 885–903]. Let $G$ be an abelian semialgebraic group over a real closed field $R$ and let $X$ be a semialgebraic subset of $G$. Then the group generated by $X$ contains a generic set and, if connected, it is divisible. More generally, the same result holds when $X$ is definable in any o-minimal expansion of $R$ which is elementarily equivalent to ${ℝ}_{\mathrm{\text{an}},\mathrm{\text{exp}}}$. We observe that the above statement is equivalent to saying: there exists an $m$ such that ${\mathrm{\Sigma }}_{i=1}^m(X-X)$ is an approximate subgroup of $G$.

Let be a Kac–Moody Lie algebra. We give an interpretation of Tits' associated group functor using representation theory of and we construct a locally compact "Kac–Moody group" G over a finite field k. Using (twin) BN-pairs (G,B,N) and (G,B^-,N) for G we show that if k is "sufficiently large", then the subgroup B^- is a non-uniform lattice in G. We have also constructed an uncountably infinite family of both uniform and non-uniform lattices in rank 2. We conjecture that these form uncountably many distinct conjugacy classes in G. The basic tool for the construction of non-uniform lattices in rank 2 is a spherical Tits system for G which we also construct.

Our main result states that a finite semiring of order > 2 with zero which is not a ring is congruence-simple if and only if it is isomorphic to a "dense" subsemiring of the endomorphism semiring of a finite idempotent commutative monoid.

We also investigate those subsemirings further, addressing e.g. the question of isomorphy.

We show that for every n-dimensional lattice the torus can be embedded with distortion into a Hilbert space. This improves the exponential upper bound of O(n^3n/2) due to Khot and Naor (FOCS 2005, Math. Ann. 2006) and gets close to their lower bound of . We also obtain tight bounds for certain families of lattices.

Our main new ingredient is an embedding that maps any point to a Gaussian function centered at u in the Hilbert space . The proofs involve Gaussian measures on lattices, the smoothing parameter of lattices and Korkine–Zolotarev bases.

We take a Galois ring $GR(p^m,g)$ and discuss about the self-dual codes and its properties over the ring. We will also describe the relationship between Clifford-Weil group and Jacobi forms by constructing the invariant polynomial ring with the complete weight enumerator.