All Stories

  1. A formal operator involving Fermatian numbers

    Article • Notes on Number Theory and Discrete Mathematics, September 2024, Prof. Marin Drinov Academic Publishing House

    Prof. Carlos M. da Fonseca

  2. On Chebyshev polynomials and the inertia of certain tridiagonal matrices

    Article • Applied Mathematics and Computation, April 2024, Elsevier

    Prof. Carlos M. da Fonseca

  3. The number of P-vertices for acyclic matrices with given nullity

    Article • Discrete Mathematics, December 2023, Elsevier

    Prof. Carlos M. da Fonseca

  4. On a sequence derived from the Laplace transform of the characteristic polynomial of the Fibonacci sequence

    Article • Notes on Number Theory and Discrete Mathematics, July 2023, Prof. Marin Drinov Academic Publishing House

    Prof. Carlos M. da Fonseca

  5. Further developments of basic trigonometric power sums

    Article • Revista de la Real Academia de Ciencias Exactas Físicas y Naturales Serie A Matemáticas, April 2023, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  6. The determinants of certain double banded (0,1) Toeplitz matrices

    Article • Miskolc Mathematical Notes, January 2023, Mathematical Notes

    Prof. Carlos M. da Fonseca

  7. An extended eigenvalue-free interval for the eccentricity matrix of threshold graphs

    Article • Korean Journal of Computational & Applied Mathematics, June 2022, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  8. Chain graph sequences and Laplacian spectra of chain graphs

    Article • Linear and Multilinear Algebra, February 2022, Taylor & Francis

    Prof. Carlos M. da Fonseca

  9. Determinantal representations for the number of subsequences without isolated odd terms

    Article • Notes on Number Theory and Discrete Mathematics, December 2021, Prof. Marin Drinov Academic Publishing House

    Prof. Carlos M. da Fonseca

  10. A periodic determinantal property for (0,1) double banded matrices

    Article • Linear and Multilinear Algebra, April 2021, Taylor & Francis

    Prof. Carlos M. da Fonseca

  11. Three Representation Types for Systems of Forms and Linear Maps

    Article • Mathematics, February 2021, MDPI AG

    Prof. Carlos M. da Fonseca

  12. Comments on the spectrum of a tridiagonal k-Toeplitz matrix

    Article • Journal of Computational and Applied Mathematics, September 2020, Elsevier

    Prof. Carlos M. da Fonseca

  13. On a closed form for derangement numbers: an elementary proof

    Article • Revista de la Real Academia de Ciencias Exactas Físicas y Naturales Serie A Matemáticas, June 2020, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  14. On nonsingular acyclic M-matrices whose inverse is also acyclic

    Article • Revista de la Real Academia de Ciencias Exactas Físicas y Naturales Serie A Matemáticas, May 2020, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  15. A Short Note on the Determinant of a Sylvester–Kac Type Matrix

    Article • International Journal of Nonlinear Sciences and Numerical Simulation, February 2020, De Gruyter

    Prof. Carlos M. da Fonseca

  16. A matrix approach to some second-order difference equations with sign-alternating coefficients

    Article • The Journal of Difference Equations and Applications, January 2020, Taylor & Francis

    Prof. Carlos M. da Fonseca

  17. Some determinantal considerations for pentadiagonal matrices

    Article • Linear and Multilinear Algebra, January 2020, Taylor & Francis

    Prof. Carlos M. da Fonseca

  18. Eigenpairs of some particular band Toeplitz matrices: A comment

    Article • Numerical Linear Algebra with Applications, October 2019, Wiley

    Prof. Carlos M. da Fonseca

  19. Line and Subdivision Graphs Determined by T4-Gain Graphs

    Article • Mathematics, October 2019, MDPI AG

    Prof. Carlos M. da Fonseca

  20. Eigenpairs of a family of tridiagonal matrices: three decades later

    Article • Acta Mathematica Hungarica, September 2019, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  21. On the continuity of the maximum size of P-sets of acyclic matrices

    Article • Discrete Mathematics, August 2019, Elsevier

    Prof. Carlos M. da Fonseca

  22. Some comments on tridiagonal (p,r)-Toeplitz matrices

    Article • Linear Algebra and its Applications, July 2019, Elsevier

    Prof. Carlos M. da Fonseca

  23. Lipschitz property for systems of linear mappings and bilinear forms

    Article • Linear Algebra and its Applications, July 2019, Elsevier

    Prof. Carlos M. da Fonseca

  24. A new type of Sylvester–Kac matrix and its spectrum

    Article • Linear and Multilinear Algebra, May 2019, Taylor & Francis

    Prof. Carlos M. da Fonseca

  25. Remarks on the eigenpairs of some Jacobi matrices

    Article • Filomat, January 2019, National Library of Serbia

    Prof. Carlos M. da Fonseca

  26. On some conjectures regarding tridiagonal matrices

    Article • Journal of Applied Mathematics and Computational Mechanics, December 2018, Czestochowa University of Technology

    Prof. Carlos M. da Fonseca

  27. Vertex types in some lexicographic products of graphs

    Article • Linear and Multilinear Algebra, July 2018, Taylor & Francis

    Prof. Carlos M. da Fonseca

  28. The minimal-ABC trees with B1-branches

    Article • PLOS One, April 2018, PLOS

    Prof. Carlos M. da Fonseca

  29. Some forbidden combinations of branches in minimal-ABC trees

    Article • Discrete Applied Mathematics, February 2018, Elsevier

    Prof. Carlos M. da Fonseca

  30. Generalized cosecant numbers and trigonometric inverse power sums

    Article • Applicable Analysis and Discrete Mathematics, January 2018, National Library of Serbia

    Prof. Carlos M. da Fonseca

  31. Topological classification of systems of bilinear and sesquilinear forms

    Article • Linear Algebra and its Applications, February 2017, Elsevier

    Prof. Carlos M. da Fonseca

  32. Some spectral bounds for the harmonic matrix

    Article • Analele ştiinţifice ale Universităţii "Ovidius" Constanţa Seria Matematică, January 2017, De Gruyter

    Prof. Carlos M. da Fonseca

  33. Classification of pairs of linear mappings between two vector spaces and between their quotient space and subspace

    Article • Linear Algebra and its Applications, November 2016, Elsevier

    Prof. Carlos M. da Fonseca

  34. Topological classification of sesquilinear forms: Reduction to the nonsingular case

    Article • Linear Algebra and its Applications, September 2016, Elsevier

    Prof. Carlos M. da Fonseca

  35. The real symmetric matrices of odd order with a P-set of maximum size

    Article • Czechoslovak Mathematical Journal, September 2016, Institute of Mathematics, Czech Academy of Sciences

    Prof. Carlos M. da Fonseca

  36. On structural properties of trees with minimal atom-bond connectivity index III: Trees with pendent paths of length three

    Article • Applied Mathematics and Computation, May 2016, Elsevier

    Prof. Carlos M. da Fonseca

  37. Basic trigonometric power sums with applications

    Article • The Ramanujan Journal, March 2016, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  38. Class of cooperative stochastic models: Exact and approximate solutions, simulations, and experiments using ionic self-assembly of nanoparticles

    Article • March 2016, American Physical Society (APS)

    Prof. Carlos M. da Fonseca

  39. On a family of trees with minimal atom-bond connectivity index

    Article • Discrete Applied Mathematics, March 2016, Elsevier

    Prof. Carlos M. da Fonseca

  40. Bruhat rank

    Article • Open Mathematics, January 2016, De Gruyter

    Prof. Carlos M. da Fonseca

  41. The singular acyclic matrices of even order with a P-set of maximum size

    Article • Filomat, January 2016, National Library of Serbia

    Prof. Carlos M. da Fonseca

  42. On Singular Values Related to DAEs in Kronecker Canonical Form

    Article • Mediterranean Journal of Mathematics, November 2015, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  43. Some comments on k -tridiagonal matrices: Determinant, spectra, and inversion

    Article • Applied Mathematics and Computation, November 2015, Elsevier

    Prof. Carlos M. da Fonseca

  44. Reflexive line graphs of trees

    Article • Journal of Algebraic Combinatorics, October 2015, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  45. Some new considerations about double nested graphs

    Article • Linear Algebra and its Applications, October 2015, Elsevier

    Prof. Carlos M. da Fonseca

  46. Eigenvalues of a certain class of tridiagonal matrices: A brief comment

    Article • Applied Mathematics and Computation, July 2015, Elsevier

    Prof. Carlos M. da Fonseca

  47. A multi-temperature kinetic Ising model and the eigenvalues of some perturbed Jacobi matrices

    Article • Applied Mathematics and Computation, May 2015, Elsevier

    Prof. Carlos M. da Fonseca

  48. The acyclic matrices with a P-set of maximum size

    Article • Linear Algebra and its Applications, March 2015, Elsevier

    Prof. Carlos M. da Fonseca

  49. Notes on the second largest eigenvalue of a graph

    Article • Linear Algebra and its Applications, January 2015, Elsevier

    Prof. Carlos M. da Fonseca

  50. The singular acyclic matrices with the second largest number of P-vertices

    Article • Linear and Multilinear Algebra, October 2014, Taylor & Francis

    Prof. Carlos M. da Fonseca

  51. Young-type inequalities and their matrix analogues

    Article • Linear and Multilinear Algebra, June 2014, Taylor & Francis

    Prof. Carlos M. da Fonseca

  52. Unifying some Pell and Fibonacci identities

    Article • Applied Mathematics and Computation, June 2014, Elsevier

    Prof. Carlos M. da Fonseca

  53. Nonsingular acyclic matrices with an extremal number of P-vertices

    Article • Linear Algebra and its Applications, February 2014, Elsevier

    Prof. Carlos M. da Fonseca

  54. Advances in Matrices, Finite and Infinite, with Applications 2014

    Article • Journal of Applied Mathematics, January 2014, Hindawi Publishing Corporation

    Prof. Carlos M. da Fonseca

  55. The eigenvalues of a family of persymmetric anti-tridiagonal 2-Hankel matrices

    Article • Applied Mathematics and Computation, December 2013, Elsevier

    Prof. Carlos M. da Fonseca

  56. The eigenpairs of a Sylvester–Kac type matrix associated with a simple model for one-dimensional deposition and evaporation

    Article • Applied Mathematics Letters, December 2013, Elsevier

    Prof. Carlos M. da Fonseca

  57. The maximum number of P-vertices of some nonsingular double star matrices

    Article • Discrete Mathematics, October 2013, Elsevier

    Prof. Carlos M. da Fonseca

  58. Nonsingular acyclic matrices with full number of P-vertices

    Article • Linear and Multilinear Algebra, August 2013, Taylor & Francis

    Prof. Carlos M. da Fonseca

  59. Remarks and open problems on the minimum permanent of acyclic doubly stochastic matrices

    Article • Linear and Multilinear Algebra, March 2013, Taylor & Francis

    Prof. Carlos M. da Fonseca

  60. The singular acyclic matrices with maximal number of P-vertices

    Article • Linear Algebra and its Applications, March 2013, Elsevier

    Prof. Carlos M. da Fonseca

  61. Nonsingular acyclic matrices with full number of P-vertices

    Article • Linear and Multilinear Algebra, January 2013, Taylor & Francis

    Prof. Carlos M. da Fonseca

  62. On a finite sum with powers of cosines

    Article • Applicable Analysis and Discrete Mathematics, January 2013, National Library of Serbia

    Prof. Carlos M. da Fonseca

  63. Some consequences of an inequality on the spectral multiplicity of graphs

    Article • Filomat, January 2013, National Library of Serbia

    Prof. Carlos M. da Fonseca

  64. Some further bounds for the Q-index of nested split graphs

    Article • Journal of Mathematical Sciences, March 2012, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  65. Connected graphs of fixed order and size with maximal

    Article • Discrete Applied Mathematics, March 2012, Elsevier

    Prof. Carlos M. da Fonseca

  66. Preface to the proceedings of the Coimbra meeting on 0–1 matrix theory and related topics

    Article • Linear Algebra and its Applications, February 2012, Elsevier

    Prof. Carlos M. da Fonseca

  67. The maximal length of a chain in the Bruhat order for a class of binary matrices

    Article • Linear Algebra and its Applications, February 2012, Elsevier

    Prof. Carlos M. da Fonseca

  68. On the rank spread of graphs

    Article • Linear and Multilinear Algebra, January 2012, Taylor & Francis

    Prof. Carlos M. da Fonseca

  69. On the Largest Size of an Antichain in the Bruhat Order for

    Article • Order, December 2011, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  70. An identity between the determinant and the permanent of Hessenberg-type matrices

    Article • Czechoslovak Mathematical Journal, December 2011, Institute of Mathematics, Czech Academy of Sciences

    Prof. Carlos M. da Fonseca

  71. New permanental bounds for Ferrers matrices

    Article • Linear Algebra and its Applications, December 2011, Elsevier

    Prof. Carlos M. da Fonseca

  72. On bounds for the index of double nested graphs

    Article • Linear Algebra and its Applications, November 2011, Elsevier

    Prof. Carlos M. da Fonseca

  73. An inverse eigenvalue problem for periodic Jacobi matrices in Minkowski spaces

    Article • Linear Algebra and its Applications, October 2011, Elsevier

    Prof. Carlos M. da Fonseca

  74. Some open questions on the Fibonacci polytope

    Article • Linear and Multilinear Algebra, March 2011, Taylor & Francis

    Prof. Carlos M. da Fonseca

  75. On the number of P-vertices of some graphs

    Article • Linear Algebra and its Applications, January 2011, Elsevier

    Prof. Carlos M. da Fonseca

  76. Sufficient conditions for positive definiteness of tridiagonal matrices revisited

    Article • Positivity, February 2010, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  77. The

    Article • Linear Algebra and its Applications, February 2010, Elsevier

    Prof. Carlos M. da Fonseca

  78. Cover matrices of posets and their spectra

    Article • Czechoslovak Mathematical Journal, November 2009, Institute of Mathematics, Czech Academy of Sciences

    Prof. Carlos M. da Fonseca

  79. On the spectra of certain directed paths

    Article • Applied Mathematics Letters, September 2009, Elsevier

    Prof. Carlos M. da Fonseca

  80. The number of faces of the tridiagonal Birkhoff polytope

    Article • Journal of Mathematical Sciences, September 2009, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  81. On (0, 1)-matrices with prescribed row and column sum vectors

    Article • Discrete Mathematics, April 2009, Elsevier

    Prof. Carlos M. da Fonseca

  82. Face counting on an Acyclic Birkhoff polytope

    Article • Linear Algebra and its Applications, February 2009, Elsevier

    Prof. Carlos M. da Fonseca

  83. Fibonacci numbers, alternating parity sequences and faces of the tridiagonal Birkhoff polytope

    Article • Discrete Mathematics, April 2008, Elsevier

    Prof. Carlos M. da Fonseca

  84. The diameter of the acyclic Birkhoff polytope

    Article • Linear Algebra and its Applications, April 2008, Elsevier

    Prof. Carlos M. da Fonseca

  85. On the multiplicities of eigenvalues of a Hermitian matrix whose graph is a tree

    Article • Annali di Matematica Pura ed Applicata (1923 -), October 2007, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  86. On the eigenvalues of some tridiagonal matrices

    Article • Journal of Computational and Applied Mathematics, March 2007, Elsevier

    Prof. Carlos M. da Fonseca

  87. An interlacing theorem for matrices whose graph is a given tree

    Article • Journal of Mathematical Sciences, December 2006, Springer Science + Business Media

    Prof. Carlos M. da Fonseca

  88. On the location of the eigenvalues of Jacobi matrices

    Article • Applied Mathematics Letters, November 2006, Elsevier

    Prof. Carlos M. da Fonseca

  89. On the inertia sets of some symmetric sign patterns

    Article • Czechoslovak Mathematical Journal, September 2006, Institute of Mathematics, Czech Academy of Sciences

    Prof. Carlos M. da Fonseca

  90. A note on the multiplicities of the eigenvalues of a graph

    Article • Linear and Multilinear Algebra, July 2005, Taylor & Francis

    Prof. Carlos M. da Fonseca

  91. On a conjecture about the μ-permanent

    Article • Linear and Multilinear Algebra, June 2005, Taylor & Francis

    Prof. Carlos M. da Fonseca

  92. A note on the spectra of tridiagonal matrices

    Article • International Journal of Mathematics and Mathematical Sciences, January 2004, Hindawi Publishing Corporation

    Prof. Carlos M. da Fonseca

  93. Explicit inverses of some tridiagonal matrices

    Article • Linear Algebra and its Applications, March 2001, Elsevier

    Prof. Carlos M. da Fonseca