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We present a general framework for balancing expressions (terms) in form of so called tree straight-line programs. The latter can be seen as circuits over the free term algebra extended by contexts (terms with a hole) and the operations…

Computational Complexity · Computer Science 2017-10-18 Moses Ganardi , Markus Lohrey

It is shown that a context-free grammar of size $m$ that produces a single string $w$ (such a grammar is also called a string straight-line program) can be transformed in linear time into a context-free grammar for $w$ of size…

Data Structures and Algorithms · Computer Science 2020-07-02 Moses Ganardi , Artur Jeż , Markus Lohrey

In mathematical phylogenetics, the time-consistent galled trees provide a simple class of rooted binary network structures that can be used to represent a variety of different biological phenomena. We study the enumerative combinatorics of…

Combinatorics · Mathematics 2025-04-24 Lily Agranat-Tamir , Michael Fuchs , Bernhard Gittenberger , Noah A. Rosenberg

We explore from an algebraic viewpoint the properties of the tree languages definable with a first-order formula involving the ancestor predicate, using the description of these languages as those recognized by iterated block products of…

Formal Languages and Automata Theory · Computer Science 2018-12-06 Martin Beaudry

This work addresses the problem of computing measures of recognisable sets of infinite trees. An algorithm is provided to compute the probability measure of a tree language recognisable by a weak alternating automaton, or equivalently…

Formal Languages and Automata Theory · Computer Science 2025-12-22 Damian Niwiński , Marcin Przybyłko , Michał Skrzypczak

Ensemble models (bagging and gradient-boosting) of relational decision trees have proved to be one of the most effective learning methods in the area of probabilistic logic models (PLMs). While effective, they lose one of the most important…

Machine Learning · Computer Science 2022-06-17 Siwen Yan , Sriraam Natarajan , Saket Joshi , Roni Khardon , Prasad Tadepalli

In 1996, Bodlaender showed the celebrated result that an optimal tree decomposition of a graph of bounded treewidth can be found in linear time. The algorithm is based on an algorithm of Bodlaender and Kloks that computes an optimal tree…

Data Structures and Algorithms · Computer Science 2020-03-19 Ernst Althaus , Sarah Ziegler

Measuring the complexity of tree structures can be beneficial in areas that use tree data structures for storage, communication, and processing purposes. This complexity can then be used to compress tree data structures to their…

Information Theory · Computer Science 2023-09-19 Amirmohammad Farzaneh , Mihai-Alin Badiu , Justin P. Coon

A simple linear-time algorithm for constructing a linear context-free tree grammar of size O(rg + r g log (n/r g))for a given input tree T of size n is presented, where g is the size of a minimal linear context-free tree grammar for T, and…

Data Structures and Algorithms · Computer Science 2018-10-09 Artur Jeż , Markus Lohrey

We study probability distributions over free algebras of trees. Probability distributions can be seen as particular (formal power) tree series [Berstel et al 82, Esik et al 03], i.e. mappings from trees to a semiring K . A widely studied…

Machine Learning · Computer Science 2008-07-21 François Denis , Amaury Habrard , Rémi Gilleron , Marc Tommasi , Édouard Gilbert

Succinct data structures give space-efficient representations of large amounts of data without sacrificing performance. They rely one cleverly designed data representations and algorithms. We present here the formalization in Coq/SSReflect…

Programming Languages · Computer Science 2019-07-03 Reynald Affeldt , Jacques Garrigue , Xuanrui Qi , Kazunari Tanaka

We propose a new approach for universal lossless text compression, based on grammar compression. In the literature, a target string $T$ has been compressed as a context-free grammar $G$ in Chomsky normal form satisfying $L(G) = \{T\}$. Such…

Data Structures and Algorithms · Computer Science 2020-03-19 Hiroaki Naganuma , Diptarama Hendrian , Ryo Yoshinaka , Ayumi Shinohara , Naoki Kobayashi

We present an algorithm for computing a maximum agreement subtree of two unrooted evolutionary trees. It takes O(n^{1.5} log n) time for trees with unbounded degrees, matching the best known time complexity for the rooted case. Our…

Computational Engineering, Finance, and Science · Computer Science 2007-05-23 Ming-Yang Kao , Tak-Wah Lam , Wing-Kin Sung , Hing-Fung Ting

The computational complexity of the isomorphism problem for regular trees, regular linear orders, and regular words is analyzed. A tree is regular if it is isomorphic to the prefix order on a regular language. In case regular languages are…

Formal Languages and Automata Theory · Computer Science 2011-02-15 Markus Lohrey , Christian Mathissen

A tree decomposition of a graph facilitates computations by grouping vertices into bags that are interconnected in an acyclic structure, hence their importance in a plethora of problems such as query evaluation over databases and inference…

Data Structures and Algorithms · Computer Science 2018-10-09 Noam Ravid , Dori Medini , Benny Kimelfeld

Frequent pattern mining is a relevant method to analyse structured data, like sequences, trees or graphs. It consists in identifying characteristic substructures of a dataset. This paper deals with a new type of patterns for tree data:…

Data Structures and Algorithms · Computer Science 2024-01-05 Romain Azaïs , Florian Ingels

Easy-first parsing relies on subtree re-ranking to build the complete parse tree. Whereas the intermediate state of parsing processing is represented by various subtrees, whose internal structural information is the key lead for later…

Computation and Language · Computer Science 2019-06-12 Zuchao Li , Jiaxun Cai , Hai Zhao

We consider the problem of {\em restructuring} compressed texts without explicit decompression. We present algorithms which allow conversions from compressed representations of a string $T$ produced by any grammar-based compression…

Data Structures and Algorithms · Computer Science 2011-07-15 Keisuke Goto , Shirou Maruyama , Shunsuke Inenaga , Hideo Bannai , Hiroshi Sakamoto , Masayuki Takeda

We propose a principled method for autoencoding with random forests. Our strategy builds on foundational results from nonparametric statistics and spectral graph theory to learn a low-dimensional embedding of the model that optimally…

Machine Learning · Statistics 2026-01-16 Binh Duc Vu , Jan Kapar , Marvin Wright , David S. Watson

We introduce Graph-Induced Sum-Product Networks (GSPNs), a new probabilistic framework for graph representation learning that can tractably answer probabilistic queries. Inspired by the computational trees induced by vertices in the context…

Machine Learning · Computer Science 2024-02-19 Federico Errica , Mathias Niepert