Exploració per autor "Fernández Sánchez, Jesús"
Ara es mostren els items 1-20 de 29
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A new phylogenetic reconstruction method based on invariants
Casanellas Rius, Marta; Fernández Sánchez, Jesús (2005)
Article
Accés obertAn attempt to use phylogenetic invariants for tree reconstruction was made at the end of the 80s and the beginning of the 90s by several authors (the initial idea due to Lake [Lake, 1987] and Cavender and Felsenstein [Cavender ... -
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
Accés obertA 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 ... -
Designing weights for quartet-based methods when data are heterogeneous across lineages
Casanellas Rius, Marta; Fernández Sánchez, Jesús; Garrote López, Marina; Sabaté Vidales, Marc (Springer Nature, 2023-06-13)
Article
Accés obertHomogeneity across lineages is a general assumption in phylogenetics according to which nucleotide substitution rates are common to all lineages. Many phylogenetic methods relax this hypothesis but keep a simple enough ... -
Distance to the stochastic part of phylogenetic varieties
Casanellas Rius, Marta; Fernández Sánchez, Jesús; Garrote López, Marina (2021-05)
Article
Accés obertModelling the substitution of nucleotides along a phylogenetic tree is usually done by a hidden Markov process. This allows to define a distribution of characters at the leaves of the trees and one might be able to obtain ... -
Embeddability and rate identifiability of Kimura 2-parameter matrices
Casanellas Rius, Marta; Fernández Sánchez, Jesús; Roca Lacostena, Jordi (2020-03-01)
Article
Accés obertDeciding 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
Accés obertIn 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 ... -
EXPRESSIO GRAFICA I DISENY ASSISTIT PER ORDINADOR (Examen 1r Quadr.)
Fernández Sánchez, Jesús (Universitat Politècnica de Catalunya, 2004-01-14)
Examen
Accés restringit a la comunitat UPC -
EXPRESSIO GRAFICA I DISENY ASSISTIT PER ORDINADOR (Examen 2n Quadr.)
Fernández Sánchez, Jesús (Universitat Politècnica de Catalunya, 2002-06-17)
Examen
Accés restringit a la comunitat UPC -
EXPRESSIO GRAFICA I DISENY ASSISTIT PER ORDINADOR (Examen 2n Quadr.)
Fernández Sánchez, Jesús (Universitat Politècnica de Catalunya, 2003-04-03)
Examen
Accés restringit a la comunitat UPC -
GEOMETRIA AFÍ I EUCLIDIANA | Parcial 2Q
Fernández Sánchez, Jesús; Álvarez Montaner, Josep; Planas Vilanova, Francesc d'Assís (Universitat Politècnica de Catalunya, 2024-03-21)
Examen
Accés restringit a la comunitat UPC -
Invariant versus classical quartet inference when evolution is heterogeneous across sites and lineages
Fernández Sánchez, Jesús; Casanellas Rius, Marta (2016)
Article
Accés obertOne reason why classical phylogenetic reconstruction methods fail to correctly infer the underlying topology is because they assume oversimplified models. In this article, we propose a quartet reconstruction method consistent ... -
Invariants, una aproximació a la filogenètica des de l'àlgebra
Fernández Sánchez, Jesús (2010)
Article
Accés obertEn els darrers anys, una nova aproximació a la reconstrucció filogenètica basada en tècniques provinents de l’àlgebra s’ha estat consolidant. Fixat un model evolutiu per a un conjunt donat d’espècies, els invariants són ... -
Lie Markov model
Sumner, Jeremy; Fernández Sánchez, Jesús; Jarvis, Peter (2012)
Article
Accés obertRecent work has discussed the importance of multiplicative closure for the Markov mod- els used in phylogenetics. For continuous-time Markov chains, a sufficient condition for multiplicative closure of a model class is ... -
Lie Markov models
Sumner, Jeremy; Fernández Sánchez, Jesús; Jarvis, Peter (2012-04-07)
Article
Accés restringit per política de l'editorialRecent work has discussed the importance of multiplicative closure for the Markov models used in phylogenetics. For continuous-time Markov chains, a sufficient condition for multiplicative closure of a model class is ensured ... -
Lie Markov models with purine/pyrimidine symmetry
Fernández Sánchez, Jesús; Sumner, Jeremy; Jarvis, Peter; Woodhams, Michael D. (2015-03-01)
Article
Accés obertContinuous-time Markov chains are a standard tool in phylogenetic inference. If homogeneity is assumed, the chain is formulated by specifying time-independent rates of substitutions between states in the chain. In applications, ... -
Lie Markov models with purine/pyrimidine symmetry
Fernández Sánchez, Jesús; Sumner, Jeremy; Jarvis, Peter; Woodhams, Michael D. (2013-06)
Report de recerca
Accés obertContinuous-time Markov chains are a standard tool in phylogenetic inference. If homogeneity is assumed, the chain is formulated by specifying time-independent rates of substitutions between states in the chain. In applications, ... -
Local description of phylogenetic group-based models
Casanellas Rius, Marta; Fernández Sánchez, Jesús; Michalek, Mateusz (2013-12)
Report de recerca
Accés obertMotivated by phylogenetics, our aim is to obtain a system of equations that de ne a phylogenetic variety on an open set containing the biologically meaningful points. In this paper we consider phylogenetic varieties de ... -
Local equations for equivariant evolutionary models
Casanellas Rius, Marta; Fernández Sánchez, Jesús; Michalek, Mateusz (2017-07-31)
Article
Accés obertPhylogenetic varieties related to equivariant substitution models have been studied largely in the last years. One of the main objectives has been finding a set of generators of the ideal of these varieties, but this has ... -
Low degree equations for phylogenetic group-based models
Casanellas Rius, Marta; Fernández Sánchez, Jesús; Michalek, Mateusz (2015)
Article
Accés obertMotivated by phylogenetics, our aim is to obtain a system of low degree equations that define a phylogenetic variety on an open set containing the biologically meaningful points. In this paper we consider phylogenetic ... -
MODELS MATEMÀTICS EN BIOLOGIA | FINAL
Casanellas Rius, Marta; Fernández Sánchez, Jesús; Huguet Casades, Gemma; Ponce Álvarez, Adrián Fernando (Universitat Politècnica de Catalunya, 2023-12-19)
Examen
Accés restringit a la comunitat UPC