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An example of a discrete pregeometry on a microscopic scale is introduced. The model is a directed dyadic acyclic graph. This is the particular case of a causal set. The particles in this model must be self-organized repetitive structures.…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Alexey L. Krugly , Ivan V. Stepanian

A particular case of a causal set is considered that is a directed dyadic acyclic graph. This is a model of a discrete pregeometry on a microscopic scale. The dynamics is a stochastic sequential growth of the graph. New vertexes of the…

General Relativity and Quantum Cosmology · Physics 2012-10-12 Alexey L. Krugly

A model of a discrete pregeometry on a microscopic scale is introduced. This model is a finite network of finite elementary processes. The mathematical description is a d-graph that is a generalization of a graph. This is the particular…

General Relativity and Quantum Cosmology · Physics 2010-04-29 Alexey L. Krugly

One of approaches to quantum gravity is different models of a discrete pregeometry. An example of a discrete pregeometry on a microscopic scale is introduced. This is the particular case of a causal set. The causal set is a locally finite…

General Relativity and Quantum Cosmology · Physics 2011-07-01 Alexey L. Krugly

The model is a particular case of causal set. This is a discrete model of spacetime in a microscopic level. In paper the most general properties of the model are investigated without any reference to a dynamics. The dynamics of the model is…

General Relativity and Quantum Cosmology · Physics 2010-09-01 Alexey L. Krugly

The spacetime discreteness of causal set theory has enabled the formulation of novel spacetime dynamics. In these so-called "growth" dynamics, a causal set spacetime is generated probabilistically by means of a random walk on certain tree…

General Relativity and Quantum Cosmology · Physics 2023-02-22 Stav Zalel

Continuum models for the spatial dynamics of growing cell populations have been widely used to investigate the mechanisms underpinning tissue development and tumour invasion. These models consist of nonlinear partial differential equations…

Tissues and Organs · Quantitative Biology 2019-07-15 Mark AJ Chaplain , Tommaso Lorenzi , Fiona R Macfarlane

To represent the causal relationships between variables, a directed acyclic graph (DAG) is widely utilized in many areas, such as social sciences, epidemics, and genetics. Many causal structure learning approaches are developed to learn the…

Machine Learning · Statistics 2025-01-14 Jianian Wang , Rui Song

We study directed random graphs (random graphs whose edges are directed) as they evolve in discrete time by the addition of nodes and edges. For two distinct evolution strategies, one that forces the graph to a condition of near acyclicity…

Statistical Mechanics · Physics 2007-05-23 Valmir C. Barbosa , Raul Donangelo , Sergio R. Souza

Real-world networks grow over time; statistical models based on node exchangeability are not appropriate. Instead of constraining the structure of the \textit{distribution} of edges, we propose that the relevant symmetries refer to the…

Social and Information Networks · Computer Science 2025-04-02 Gecia Bravo-Hermsdorff , Lee M. Gunderson , Kayvan Sadeghi

We consider the problem of learning causal directed acyclic graphs from an observational joint distribution. One can use these graphs to predict the outcome of interventional experiments, from which data are often not available. We show…

Machine Learning · Statistics 2016-08-18 Jonas Peters , Joris Mooij , Dominik Janzing , Bernhard Schölkopf

We begin by describing a sequential growth model in which the universe grows one element at a time in discrete time steps. At each step, the process has the form of a causal set and the "completed" universe is given by a path consisting of…

General Relativity and Quantum Cosmology · Physics 2012-04-27 Stan Gudder

Estimating the structure of directed acyclic graphs (DAGs) of features (variables) plays a vital role in revealing the latent data generation process and providing causal insights in various applications. Although there have been many…

Machine Learning · Computer Science 2024-03-06 Shaohua Fan , Shuyang Zhang , Xiao Wang , Chuan Shi

We consider graphical models based on a recursive system of linear structural equations. This implies that there is an ordering, $\sigma$, of the variables such that each observed variable $Y_v$ is a linear function of a variable specific…

Methodology · Statistics 2019-06-28 Y. Samuel Wang , Mathias Drton

We consider a covariant causal set approach to discrete quantum gravity. We first review the microscopic picture of this approach. In this picture a universe grows one element at a time and its geometry is determined by a sequence of…

General Relativity and Quantum Cosmology · Physics 2022-09-01 Stan Gudder

The Causal Set approach to quantum gravity asserts that spacetime, at its smallest length scale, has a discrete structure. This discrete structure takes the form of a locally finite order relation, where the order, corresponding with the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 David Rideout

Discovery of causal relations is fundamental for understanding the dynamics of complex systems. While causal interactions are well defined for acyclic systems that can be separated into causally effective subsystems, a mathematical…

Data Analysis, Statistics and Probability · Physics 2017-10-11 Daniel Harnack , Erik Laminski , Klaus Richard Pawelzik

In this paper we investigate the growth rate of the number of all possible paths in graphs with respect to their length in an exact analytical way. Apart from the typical rates of growth, i.e. exponential or polynomial, we identify…

Dynamical Systems · Mathematics 2007-05-23 Vasileios Basios , Gian-Luigi Forti , Gregoire Nicolis

We extend Cellular Automata to time-varying discrete geometries. In other words we formalize, and prove theorems about, the intuitive idea of a discrete manifold which evolves in time, subject to two natural constraints: the evolution does…

Discrete Mathematics · Computer Science 2018-07-17 Pablo Arrighi , Clément Chouteau , Stefano Facchini , Simon Martiel

We give methods for Bayesian inference of directed acyclic graphs, DAGs, and the induced causal effects from passively observed complete data. Our methods build on a recent Markov chain Monte Carlo scheme for learning Bayesian networks,…

Machine Learning · Computer Science 2020-11-19 Jussi Viinikka , Antti Hyttinen , Johan Pensar , Mikko Koivisto
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