Now showing items 1-8 of 8

    • An open set of 4×4 embeddable matrices whose principal logarithm is not a Markov generator 

      Casanellas Rius, Marta; Fernández Sánchez, Jesús; Roca Lacostena, Jordi (Taylor & Francis, 2020-12-17)
      Article
      Open Access
      A Markov matrix is embeddable if it can represent a homogeneous continuous-time Markov process. It is well known that if a Markov matrix has real and pairwise-different eigenvalues, then the embeddability can be determined ...
    • Embeddability and rate identifiability of Kimura 2-parameter matrices 

      Casanellas Rius, Marta; Fernández Sánchez, Jesús; Roca Lacostena, Jordi (2020-03-01)
      Article
      Open Access
      Deciding whether a substitution matrix is embeddable (i.e. the corresponding Markov process has a continuous-time realization) is an open problem even for 4×4 matrices. We study the embedding problem and rate identifiability ...
    • Embeddability of centrosymmetric matrices capturing the double-helix structure in natural and synthetic DNA 

      Ardiyansyah, Muhammad; Kosta, Dimitra; Roca Lacostena, Jordi (Springer Nature, 2023-04-05)
      Article
      Open Access
      In this paper, we discuss the embedding problem for centrosymmetric matrices, which are higher order generalizations of the matrices occurring in strand symmetric models. These models capture the substitution symmetries ...
    • Embeddability of Kimura 3ST Markov matrices 

      Roca Lacostena, Jordi; Fernández Sánchez, Jesús (2018-05-14)
      Article
      Open Access
      In this note, we characterize the embeddability of generic Kimura 3ST Markov matrices in terms of their eigenvalues. As a consequence, we are able to compute the volume of such matrices relative to the volume of all Markov ...
    • Looking for transcription factor binding sites 

      Roca Lacostena, Jordi (Universitat Politècnica de Catalunya, 2015-10)
      Master thesis
      Restricted access - confidentiality agreement
      Covenantee:   Institut d'Investigació en Intel·ligència Artificial
    • Sufficient and necessary conditions for solution finding in valuation-based systems 

      Roca Lacostena, Jordi; Cerquides, Jesús; Pouly, Marc (2019-11-01)
      Article
      Open Access
      Valuation algebras abstract a large number of formalisms for automated reasoning and enable the definition of generic inference procedures. Many of these formalisms provide some notion of solution. Typical examples are ...
    • The embedding problem for Markov matrices 

      Casanellas Rius, Marta; Fernández Sánchez, Jesús; Roca Lacostena, Jordi (2023-01-01)
      Article
      Open Access
      Characterizing whether a Markov process of discrete random variables has a homogeneous continuous-time realization is a hard problem. In practice, this problem reduces to deciding when a given Markov matrix can be written ...
    • The embedding problem for Markov matrices 

      Roca Lacostena, Jordi (Universitat Politècnica de Catalunya, 2021-05-18)
      Doctoral thesis
      Open Access
      The goal of this thesis is to solve the embedding problem for Markov matrices, posed by Gustav Elfving in1937. A Markov matrix is non-negative square matrix whose rows sum to 1. We say that such a matrix M is embeddable ...