Now showing items 1-7 of 7

    • 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 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 

      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 ...
    • 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 ...