English
Related papers

Related papers: Grammar-based Compression of Unranked Trees

200 papers

We use the recently developed theory of forest algebras to find algebraic characterizations of the languages of unranked trees and forests definable in various logics. These include the temporal logics CTL and EF, and first-order logic over…

Logic in Computer Science · Computer Science 2015-07-01 Mikolaj Bojanczyk , Igor Walukiewicz , Howard Straubing

We introduce a new class of straight-line programs (SLPs), named the Lyndon SLP, inspired by the Lyndon trees (Barcelo, 1990). Based on this SLP, we propose a self-index data structure of $O(g)$ words of space that can be built from a…

Data Structures and Algorithms · Computer Science 2020-04-28 Kazuya Tsuruta , Dominik Köppl , Yuto Nakashima , Shunsuke Inenaga , Hideo Bannai , Masayuki Takeda

Efficient methods for storing and querying are critical for scaling high-order n-gram language models to large corpora. We propose a language model based on compressed suffix trees, a representation that is highly compact and can be easily…

Computation and Language · Computer Science 2016-08-17 Ehsan Shareghi , Matthias Petri , Gholamreza Haffari , Trevor Cohn

We consider the problem of evaluating regular spanners over compressed documents, i.e., we wish to solve evaluation tasks directly on the compressed data, without decompression. As compressed forms of the documents we use straight-line…

Data Structures and Algorithms · Computer Science 2021-01-27 Markus L. Schmid , Nicole Schweikardt

Pairwise ordered tree alignment are combinatorial objects that appear in RNA secondary structure comparison. However, the usual representation of tree alignments as supertrees is ambiguous, i.e. two distinct supertrees may induce identical…

Quantitative Methods · Quantitative Biology 2016-03-08 Cedric Chauve , Julien Courtiel , Yann Ponty

We consider a temporal logic EF+F^-1 for unranked, unordered finite trees. The logic has two operators: EF\phi, which says "in some proper descendant \phi holds", and F^-1\phi, which says "in some proper ancestor \phi holds". We present an…

Logic in Computer Science · Computer Science 2015-07-01 Mikolaj Bojanczyk

Rooted bifurcating trees are mathematical objects used to model evolutionary relationships and arise naturally in both coalescent theory and phylogenetics. Recent numerical representations of tree topologies, known as F-matrices, allow for…

Offering rich contexts to Large Language Models (LLMs) has shown to boost the performance in various tasks, but the resulting longer prompt would increase the computational cost and might exceed the input limit of LLMs. Recently, some…

Computation and Language · Computer Science 2025-09-30 Wenhao Mao , Chengbin Hou , Tianyu Zhang , Xinyu Lin , Ke Tang , Hairong Lv

Regression trees and their ensemble methods are popular methods for nonparametric regression: they combine strong predictive performance with interpretable estimators. To improve their utility for locally smooth response surfaces, we study…

Methodology · Statistics 2021-09-13 Sören R. Künzel , Theo F. Saarinen , Edward W. Liu , Jasjeet S. Sekhon

Given two messages - as linear sequences of letters, it is immediate to determine whether one can be transformed into the other by simple substitution cipher of the letters. On the other hand, if the letters are carried as labels on nodes…

Discrete Mathematics · Computer Science 2022-04-14 Florian Ingels , Romain Azaïs

The definition of $k^{th}$-order empirical entropy of strings is extended to node labelled binary trees. A suitable binary encoding of tree straight-line programs (that have been used for grammar-based tree compression before) is shown to…

Data Structures and Algorithms · Computer Science 2020-05-21 Danny Hucke , Markus Lohrey , Louisa Seelbach Benkner

Vision language models (VLMs) excel at zero-shot visual classification, but their performance on fine-grained tasks and large hierarchical label spaces is understudied. This paper investigates whether structured, tree-based reasoning can…

Computer Vision and Pattern Recognition · Computer Science 2025-09-15 Sary Elmansoury , Islam Mesabah , Gerrit Großmann , Peter Neigel , Raj Bhalwankar , Daniel Kondermann , Sebastian J. Vollmer

We consider the problem of lossless compression of binary trees, with the aim of reducing the number of code bits needed to store or transmit such trees. A lossless grammar-based code is presented which encodes each binary tree into a…

Information Theory · Computer Science 2013-04-30 Jie Zhang , En-hui Yang , John C. Kieffer

We present an algorithm for computing the Lyndon factorization of a string that is given in grammar compressed form, namely, a Straight Line Program (SLP). The algorithm runs in $O(n^4 + mn^3h)$ time and $O(n^2)$ space, where $m$ is the…

Data Structures and Algorithms · Computer Science 2013-04-29 Tomohiro I , Yuto Nakashima , Shunsuke Inenaga , Hideo Bannai , Masayuki Takeda

Many discrete mathematics problems in phylogenetics are defined in terms of the relative labeling of pairs of leaf-labeled trees. These relative labelings are naturally formalized as tanglegrams, which have previously been an object of…

Populations and Evolution · Quantitative Biology 2015-07-20 Frederick A Matsen , Sara Billey , Arnold Kas , Matjaž Konvalinka

Language models generate reasoning sequentially, preventing them from decoupling irrelevant exploration paths during search. We introduce Tree-Structured Language Modeling (TSLM), which uses special tokens to encode branching structure,…

Computation and Language · Computer Science 2026-02-02 Doyoung Kim , Jaehyeok Doo , Minjoon Seo

This paper is an extended abstract of an analysis of term rewriting where the terms in the rewrite rules as well as the term to be rewritten are compressed by a singleton tree grammar (STG). This form of compression is more general than…

Logic in Computer Science · Computer Science 2013-02-27 Manfred Schmidt-Schauss

This paper presents a brand new nonparametric density estimation strategy named the best-scored random forest density estimation whose effectiveness is supported by both solid theoretical analysis and significant experimental performance.…

Machine Learning · Statistics 2019-05-10 Hanyuan Hang , Hongwei Wen

Suffix trees are one of the most versatile data structures in stringology, with many applications in bioinformatics. Their main drawback is their size, which can be tens of times larger than the input sequence. Much effort has been put into…

Data Structures and Algorithms · Computer Science 2017-12-18 Andrea Farruggia , Travis Gagie , Gonzalo Navarro , Simon J. Puglisi , Jouni Sirén

We study the problem of generating, ranking and unranking of unlabeled ordered trees whose nodes have maximum degree of $\Delta$. This class of trees represents a generalization of chemical trees. A chemical tree is an unlabeled tree in…

Computational Complexity · Computer Science 2016-08-22 Mahdi Amani , Abbas Nowzari-Dalini