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Tree ensembles are very popular machine learning models, known for their effectiveness in supervised classification and regression tasks. Their performance derives from aggregating predictions of multiple decision trees, which are renowned…

Optimization and Control · Mathematics 2025-01-14 Lorenzo Bonasera , Emilio Carrizosa

Cayley's formula is a fundamental result in combinatorics that counts the number of labeled trees on n vertices. While existing proofs use approaches such as Prufer sequences and the Matrix-Tree Theorem, we give a combinatorial proof that…

Combinatorics · Mathematics 2026-02-11 Helia Karisani , Mohammadreza Daneshvaramoli

For a labelled tree on the vertex set $[n]:=\{1,2,..., n\}$, define the direction of each edge $ij$ to be $i\to j$ if $i<j$. The indegree sequence of $T$ can be considered as a partition $\lambda \vdash n-1$. The enumeration of trees with a…

Combinatorics · Mathematics 2009-04-02 Rosena R. X. Du , Jingbin Yin

We apply so-called tree straight-line programs to the problem of lossless compression of binary trees. We derive upper bound on the maximal pointwise redundancy (or worst-case redundancy) that improve previous bounds obtained by Zhang,…

Information Theory · Computer Science 2017-02-01 Danny Hucke , Markus Lohrey

We present a new universal source code for distributions of unlabeled binary and ordinal trees that achieves optimal compression to within lower order terms for all tree sources covered by existing universal codes. At the same time, it…

Data Structures and Algorithms · Computer Science 2021-09-06 J. Ian Munro , Patrick K. Nicholson , Louisa Seelbach Benkner , Sebastian Wild

Arthur Cayley famously proved that there are n to the power n-2 labeled trees on n vertices. Here we go much further and show how to enumerate, fully automatically, labeled trees such that every vertex has a number of neighbors that belongs…

Combinatorics · Mathematics 2022-02-22 Shalosh B. Ekhad , Doron Zeilberger

Large language models achieve strong reasoning performance, yet existing decoding strategies either explore blindly (random sampling) or redundantly (independent multi-sampling). We propose Entropy-Tree, a tree-based decoding method that…

Computation and Language · Computer Science 2026-01-23 Longxuan Wei , Yubo Zhang , Zijiao Zhang , Zhihu Wang , Shiwan Zhao , Tianyu Huang , Huiting Zhao , Chenfei Liu , Shenao Zhang , Junchi Yan

We prove a new formula for the generating function of multitype Cayley trees counted according to their degree distribution. Using this formula we recover and extend several enumerative results about trees. In particular, we extend some…

Combinatorics · Mathematics 2013-04-08 Olivier Bernardi , Alejandro H. Morales

We consider the problem of stabilizing an unstable plant driven by bounded noise over a digital noisy communication link, a scenario at the heart of networked control. To stabilize such a plant, one needs real-time encoding and decoding…

Information Theory · Computer Science 2016-06-09 Anatoly Khina , Wael Halbawi , Babak Hassibi

For a labeled tree on the vertex set $\set{1,2,\ldots,n}$, the local direction of each edge $(i\,j)$ is from $i$ to $j$ if $i<j$. For a rooted tree, there is also a natural global direction of edges towards the root. The number of edges…

Combinatorics · Mathematics 2022-03-22 Heesung Shin , Jiang Zeng

We study some essential arithmetic properties of a new tree-based number representation, {\em hereditarily binary numbers}, defined by applying recursively run-length encoding of bijective base-2 digits. Our representation expresses giant…

Data Structures and Algorithms · Computer Science 2013-06-06 Paul Tarau

In this paper, we provide algorithms to rank and unrank certain degree-restricted classes of Cayley trees (spanning trees of the n-vertex complete graph). Specifically, we consider classes of trees that have a given set of leaves or a fixed…

Combinatorics · Mathematics 2010-09-13 Jeffrey B. Remmel , S. Gill Williamson

In this paper, we develop a new method to produce explicit formulas for the number $f_{G}(n)$ of rooted spanning forests in the circulant graphs $ G=C_{n}(s_1,s_2,\ldots,s_k)$ and $ G=C_{2n}(s_1,s_2,\ldots,s_k,n).$ These formulas are…

Combinatorics · Mathematics 2019-07-08 L. A. Grunwald , I. A. Mednykh

We study the asymptotic number of certain monotonically labeled increasing trees arising from a generalized evolution process. The main difference between the presented model and the classical model of binary increasing trees is that the…

Combinatorics · Mathematics 2019-10-30 Olivier Bodini , Antoine Genitrini , Bernhard Gittenberger , Stephan Wagner

Hash codes are a very efficient data representation needed to be able to cope with the ever growing amounts of data. We introduce a random forest semantic hashing scheme with information-theoretic code aggregation, showing for the first…

Computer Vision and Pattern Recognition · Computer Science 2015-04-20 Qiang Qiu , Guillermo Sapiro , Alex Bronstein

We present a new algorithm to explore or count the numerical semigroups of a given genus which uses the unleaved version of the tree of numerical semigroups. In the unleaved tree there are no leaves rather than the ones at depth equal to…

Combinatorics · Mathematics 2026-05-13 Maria Bras-Amorós

The structure of an evolving network contains information about its past. Extracting this information efficiently, however, is, in general, a difficult challenge. We formulate a fast and efficient method to estimate the most likely history…

Physics and Society · Physics 2020-09-16 Gábor Timár , Rui A. da Costa , Sergey N. Dorogovtsev , José F. F. Mendes

By extending the breadth first search algorithm to any d-type critical or subcritical irreducible branching forest, we show that such forests may be encoded through d independent, integer valued, d-dimensional random walks. An application…

Probability · Mathematics 2014-03-11 Loïc Chaumont , Rongli Liu

In this short note we prove that, given two (not necessarily binary) rooted phylogenetic trees T_1, T_2 on the same set of taxa X, where |X|=n, the hybridization number of T_1 and T_2 can be computed in time O^{*}(2^n) i.e. O(2^{n}…

Populations and Evolution · Quantitative Biology 2013-12-05 Leo van Iersel , Steven Kelk , Nela Lekic , Leen Stougie

Cayley's formula states that there are $n^{n-2}$ spanning trees in the complete graph on $n$ vertices; it has been proved in more than a dozen different ways over its 150 year history. The complete graphs are a special case of threshold…

Combinatorics · Mathematics 2013-01-09 Stephen R. Chestnut , Donniell E. Fishkind