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We present an improved orderly algorithm for constructing all unlabelled lattices up to a given size, that is, an algorithm that constructs the minimal element of each isomorphism class relative to some total order. Our algorithm employs a…

Combinatorics · Mathematics 2019-12-23 Volker Gebhardt , Stephen Tawn

Modular lattices, introduced by R. Dedekind, are an important subvariety of lattices that includes all distributive lattices. Heitzig and Reinhold developed an algorithm to enumerate, up to isomorphism, all finite lattices up to size 18.…

Combinatorics · Mathematics 2015-09-22 Peter Jipsen , Nathan Lawless

Lattices are simplified by removing some of their doubly irreducible elements, resulting in smaller lattices called racks. All vertically indecomposable modular racks of $n \le 40$ elements are listed, and the numbers of all modular…

Combinatorics · Mathematics 2025-04-16 Jukka Kohonen

We introduce an algorithm for computing closure systems derived from a family of implications on a set. Semilattices presentations are explored and used in conjunction with the algorithm to compute various types of lattices freely generated…

Combinatorics · Mathematics 2010-04-26 Jean Yves Semegni , Marcel Wild

A vertical 2-sum of a two-coatom lattice $L$ and a two-atom lattice $U$ is obtained by removing the top of $L$ and the bottom of $U$, and identifying the coatoms of $L$ with the atoms of $U$. This operation creates one or two nonisomorphic…

Combinatorics · Mathematics 2020-07-08 Jukka Kohonen

The main objective of this thesis is a classification project for integral lattices. Using Kneser's neighbour method we have developed the computer program tn to classify complete genera of integral lattices. Main results are detailed…

Metric Geometry · Mathematics 2007-05-23 Boris Hemkemeier

Part B (of a project involving four Parts) is about "bases of lines", a concept introduced by C. Herrmann and the author in the late 80's. Bases of lines attempt to describe a given modular lattice in a geometric way akin to how projective…

Combinatorics · Mathematics 2022-02-10 Marcel Wild

A Lattice is a partially ordered set where both least upper bound and greatest lower bound of any pair of elements are unique and exist within the set. K\"{o}tter and Kschischang proved that codes in the linear lattice can be used for error…

Discrete Mathematics · Computer Science 2021-09-30 Pranab Basu

A lattice L is slim if it is finite and the set of its join-irreducible elements contains no three-element antichain. Slim, semimodular lattices were previously characterized by G. Cz\'edli and E.T. Schmidt as the duals of the lattices…

Rings and Algebras · Mathematics 2012-08-31 Gábor Czédli , Tamás Dékány , László Ozsvárt , Nóra Szakács , Balázs Udvari

In this paper, we count all non-isomorphic lattices on $n$ elements, containing four reducible elements and having nullity three. This work is in respect of Birkhoff's open problem (which is NP-complete) of counting all finite lattices on…

Combinatorics · Mathematics 2025-09-26 Ashok Nivrutti Bhavale

This article is the second part of an essay dedicated to lattices freely generated by posets within a variety. The first part dealt with four easy varieties while this part is concerned with finitely generated varieties. Here we present a…

Combinatorics · Mathematics 2010-07-12 Jean Yves Semegni , Marcel Wild

We classify the unimodular Euclidean integral lattices of rank 29 by developing an elementary, yet very efficient, inductive method. As an application, we determine the isometry classes of even lattices of rank at most 28 and prime…

Number Theory · Mathematics 2026-01-28 Gaëtan Chenevier , Olivier Taïbi

We give a new algorithm for generating Greechie diagrams with arbitrary chosen number of atoms or blocks (with 2,3,4,... atoms) and provide a computer program for generating the diagrams. The results show that the previous algorithm does…

Quantum Physics · Physics 2007-05-23 Brendan D. McKay , Norman D. Megill , Mladen Pavicic

In 2020 Bhavale and Waphare introduced the concept of a nullity of a poset as nullity of its cover graph. In 2003 Pawar and Waphare counted all non-isomorphic lattices on n elements and n edges, which are precisely lattices of nullity one.…

Combinatorics · Mathematics 2025-03-19 B. P. Aware , A. N. Bhavale

We consider a variation of Construction A of lattices from linear codes based on two classes of number fields, totally real and CM Galois number fields. We propose a generic construction with explicit generator and Gram matrices, then focus…

Information Theory · Computer Science 2016-04-07 Xiaolu Hou , Frédérique Oggier

We survey results concerning special elements of nine types (modular, lower-modular, upper-modular, cancellable, distributive, codistributive, standard, costandard and neutral elements) in the lattice of all semigroup varieties and certain…

Group Theory · Mathematics 2021-04-13 B. M. Vernikov

This paper is the first part of a study devoted to description of modular elements in the lattices of semigroup and epigroup varieties. We provide strengthened necessary and sufficient conditions under which a semigroup or epigroup variety…

Group Theory · Mathematics 2025-11-25 Vyacheslav Yu. Shaprynski\vı , Dmitry V. Skokov

In 2002 Thakare et al.\ counted non-isomorphic lattices on $n$ elements, having nullity up to two. In 2020 Bhavale and Waphare introduced the concept of RC-lattices as the class of all lattices in which all the reducible elements are…

Combinatorics · Mathematics 2025-02-12 A. N. Bhavale

By median we mean a scheme that inputs three element of a lattice, and outputs an element that is an average of the three inputs in a certain sense. The medians of a given finite lattice form a new lattice that is usually larger than the…

Combinatorics · Mathematics 2026-03-19 Leen Aburub , Gergo Gyenizse

Conditional neural text generation models generate high-quality outputs, but often concentrate around a mode when what we really want is a diverse set of options. We present a search algorithm to construct lattices encoding a massive number…

Computation and Language · Computer Science 2022-05-04 Jiacheng Xu , Siddhartha Reddy Jonnalagadda , Greg Durrett
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