All Stories

  1. Epimorphisms and pseudovarieties of semigroups

    Article • Semigroup Forum, November 2025, Springer Science + Business Media

    Jorge Almeida

  2. Preface of the Special Issue Dedicated to Selected Semigroup Papers from the Conference on Theoretical and Computational Algebra 2024

    Article • Semigroup Forum, August 2025, Springer Science + Business Media

    Jorge Almeida

  3. Pseudovarieties of semigroups

    Article • Asian-European Journal of Mathematics, May 2025, World Scientific Pub Co Pte Lt

    Jorge Almeida

  4. Stone Pseudovarieties

    Article • Results in Mathematics, September 2024, Springer Science + Business Media

    Jorge Almeida

  5. Equidivisibility and profinite coproduct

    Article • Quaestiones Mathematicae, February 2023, Informa UK Limited

    Jorge Almeida

  6. What makes a Stone topological algebra Profinite

    Article • Algebra Universalis, January 2023, Springer Science + Business Media

    Jorge Almeida

  7. Locally countable pseudovarieties

    Article • Publicacions Matemàtiques, January 2023, Universitat Autonoma de Barcelona

    Jorge Almeida

  8. The rank of variants of nilpotent pseudovarieties

    Article • Journal of Algebra, November 2022, Elsevier

    Jorge Almeida

  9. Recognizing pro-

    Article • Forum Mathematicum, July 2022, De Gruyter

    Jorge Almeida

  10. Profinite topologies

    Article • September 2021, European Mathematical Publishing House

    Jorge Almeida

  11. Binary patterns in the Prouhet-Thue-Morse sequence

    Article • Discrete Mathematics & Theoretical Computer Science, August 2021, Centre pour la Communication Scientifique Directe (CCSD)

    Jorge Almeida

  12. Groups of Bifix Codes

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  13. Prelude: Profinite Integers

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  14. Profinite Groups and Semigroups

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  15. Introduction

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  16. Profinite Semigroups and Symbolic Dynamics

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  17. Shift Spaces

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  18. Sturmian Sets and Tree Sets

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  19. The Schützenberger Group of a Minimal Set

    Article • January 2020, Springer Science + Business Media

    Jorge Almeida

  20. On the group of a rational maximal bifix code

    Article • Forum Mathematicum, December 2019, De Gruyter

    Jorge Almeida

  21. Representations of relatively free profinite semigroups, irreducibility, and order primitivity

    Article • Transactions of the American Mathematical Society, December 2019, American Mathematical Society (AMS)

    Jorge Almeida

  22. The linear nature of pseudowords

    Article • Publicacions Matemàtiques, July 2019, Universitat Autonoma de Barcelona

    Jorge Almeida

  23. Correction to: Pseudovarieties of Ordered Completely Regular Semigroups

    Article • Results in Mathematics, April 2019, Springer Science + Business Media

    Jorge Almeida

  24. Pseudovarieties of Ordered Completely Regular Semigroups

    Article • Results in Mathematics, March 2019, Springer Science + Business Media

    Jorge Almeida

  25. Towards a pseudoequational proof theory

    Article • Portugaliae Mathematica, December 2018, European Mathematical Publishing House

    Jorge Almeida

  26. Nilpotency and strong nilpotency for finite semigroups

    Article • The Quarterly Journal of Mathematics, November 2018, Oxford University Press (OUP)

    Jorge Almeida

  27. The ω-inequality problem for concatenation hierarchies of star-free languages

    Article • Forum Mathematicum, May 2018, De Gruyter

    Jorge Almeida

  28. A note on the finite basis and finite rank properties for pseudovarieties of semigroups

    Article • Semigroup Forum, December 2017, Springer Science + Business Media

    Jorge Almeida

  29. The pro-nilpotent group topology on a free group

    Article • Journal of Algebra, June 2017, Elsevier

    Jorge Almeida

  30. Equidivisible pseudovarieties of semigroups

    Article • Publicationes Mathematicae Debrecen, April 2017, University of Debrecen/ Debreceni Egyetem

    Jorge Almeida

  31. Complete κ-reducibility of pseudovarieties of the form DRH

    Article • International Journal of Algebra and Computation, March 2017, World Scientific Pub Co Pte Lt

    Jorge Almeida

  32. Commutative Positive Varieties of Languages

    Article • Acta Cybernetica, January 2017, University of Szeged

    Jorge Almeida

  33. Reducibility vs. definability for pseudovarieties of semigroups

    Article • International Journal of Algebra and Computation, November 2016, World Scientific Pub Co Pte Lt

    Jorge Almeida

  34. A geometric interpretation of the Schützenberger group of a minimal subshift

    Article • Arkiv för matematik, October 2016, International Press of Boston

    Jorge Almeida

  35. On the irreducibility of pseudovarieties of semigroups

    Article • Journal of Pure and Applied Algebra, April 2016, Elsevier

    Jorge Almeida

  36. Semisimple Synchronizing Automata and the Wedderburn-Artin Theory

    Article • International Journal of Foundations of Computer Science, February 2016, World Scientific Pub Co Pte Lt

    Jorge Almeida

  37. Reducibility of pointlike problems

    Article • Semigroup Forum, December 2015, Springer Science + Business Media

    Jorge Almeida

  38. A NOTE ON PSEUDOVARIETIES OF COMPLETELY REGULAR SEMIGROUPS

    Article • Bulletin of the Australian Mathematical Society, June 2015, Cambridge University Press

    Jorge Almeida

  39. On fixed points of the lower set operator

    Article • International Journal of Algebra and Computation, February 2015, World Scientific Pub Co Pte Lt

    Jorge Almeida

  40. On Decidability of Intermediate Levels of Concatenation Hierarchies

    Article • January 2015, Springer Science + Business Media

    Jorge Almeida

  41. McCammond’s normal forms for free aperiodic semigroups revisited

    Article • LMS Journal of Computation and Mathematics, January 2015, Wiley

    Jorge Almeida

  42. Iterated periodicity over finite aperiodic semigroups

    Article • European Journal of Combinatorics, April 2014, Elsevier

    Jorge Almeida

  43. Closures of regular languages for profinite topologies

    Article • Semigroup Forum, March 2014, Springer Science + Business Media

    Jorge Almeida

  44. Semisimple Synchronizing Automata and the Wedderburn-Artin Theory

    Article • January 2014, Springer Science + Business Media

    Jorge Almeida

  45. Presentations of Schützenberger groups of minimal subshifts

    Article • Israel Journal of Mathematics, August 2013, Springer Science + Business Media

    Jorge Almeida

  46. On the Semigroup of Equational Classes of Finite Functions

    Article • May 2013, Institute of Electrical & Electronics Engineers (IEEE)

    Jorge Almeida

  47. ON THE TRANSITION SEMIGROUPS OF CENTRALLY LABELED RAUZY GRAPHS

    Article • International Journal of Algebra and Computation, March 2012, World Scientific Pub Co Pte Lt

    Jorge Almeida

  48. Idempotent-generated semigroups and pseudovarieties

    Article • Proceedings of the Edinburgh Mathematical Society, June 2011, Cambridge University Press

    Jorge Almeida

  49. Semidirect product with an order-computable pseudovariety and tameness

    Article • Semigroup Forum, June 2010, Springer Science + Business Media

    Jorge Almeida

  50. A counterexample to a conjecture concerning concatenation hierarchies

    Article • Information Processing Letters, December 2009, Elsevier

    Jorge Almeida

  51. Gérard Lallement (1935–2006)

    Article • Semigroup Forum, June 2009, Springer Science + Business Media

    Jorge Almeida

  52. Infinite-vertex free profinite semigroupoids and symbolic dynamics

    Article • Journal of Pure and Applied Algebra, May 2009, Elsevier

    Jorge Almeida

  53. Complexity of the identity checking problem for finite semigroups

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

    Jorge Almeida

  54. Rational codes and free profinite monoids

    Article • Journal of the London Mathematical Society, March 2009, Wiley

    Jorge Almeida

  55. Matrix Mortality and the Černý-Pin Conjecture

    Article • January 2009, Springer Science + Business Media

    Jorge Almeida

  56. Representation theory of finite semigroups, semigroup radicals and formal language theory

    Article • Transactions of the American Mathematical Society, October 2008, American Mathematical Society (AMS)

    Jorge Almeida

  57. Description and analysis of a bottom-up DFA minimization algorithm

    Article • Information Processing Letters, July 2008, Elsevier

    Jorge Almeida

  58. Pointlike sets with respect to R and J

    Article • Journal of Pure and Applied Algebra, March 2008, Elsevier

    Jorge Almeida

  59. Profinite groups associated with weakly primitive substitutions

    Article • Journal of Mathematical Sciences, July 2007, Springer Science + Business Media

    Jorge Almeida

  60. COMPLETE REDUCIBILITY OF PSEUDOVARIETIES

    Article • June 2007, World Scientific Pub Co Pte Lt

    Jorge Almeida

  61. An automata-theoretic approach to the word problem for ω -terms over R

    Article • Theoretical Computer Science, February 2007, Elsevier

    Jorge Almeida

  62. Complete reducibility of systems of equations with respect to R

    Article • Portugaliae Mathematica, January 2007, European Mathematical Publishing House

    Jorge Almeida

  63. SUBWORD COMPLEXITY OF PROFINITE WORDS AND SUBGROUPS OF FREE PROFINITE SEMIGROUPS

    Article • International Journal of Algebra and Computation, April 2006, World Scientific Pub Co Pte Lt

    Jorge Almeida

  64. Tameness of Pseudovariety Joins Involving ${\sf R}$

    Article • Monatshefte für Mathematik, September 2005, Springer Science + Business Media

    Jorge Almeida

  65. TAMENESS OF THE PSEUDOVARIETY OF ABELIAN GROUPS

    Article • International Journal of Algebra and Computation, April 2005, World Scientific Pub Co Pte Lt

    Jorge Almeida

  66. The pseudovariety of semigroups of triangular matrices over a finite field

    Article • RAIRO - Theoretical Informatics and Applications, January 2005, EDP Sciences

    Jorge Almeida

  67. The globals of pseudovarieties of ordered semigroups containingB2and an application to a problem proposed by Pin

    Article • RAIRO - Theoretical Informatics and Applications, January 2005, EDP Sciences

    Jorge Almeida

  68. THE GLOBALS OF SOME SUBPSEUDOVARIETIES OF $\mathsf{DA}$

    Article • International Journal of Algebra and Computation, October 2004, World Scientific Pub Co Pte Lt

    Jorge Almeida

  69. THE EQUATIONAL THEORY OF ω-TERMS FOR FINITE ${\mathcal R}$-TRIVIAL SEMIGROUPS

    Article • July 2004, World Scientific Pub Co Pte Lt

    Jorge Almeida

  70. Semidirect products with the pseudovariety of all finite groups

    Article • July 2003, World Scientific Pub Co Pte Lt

    Jorge Almeida

  71. PROFINITE IDENTITIES FOR FINITE SEMIGROUPS WHOSE SUBGROUPS BELONG TO A GIVEN PSEUDOVARIETY

    Article • Journal of Algebra and Its Applications, June 2003, World Scientific Pub Co Pte Lt

    Jorge Almeida

  72. Tameness of Some Locally Trivial Pseudovarieties

    Article • Communications in Algebra, January 2003, Taylor & Francis

    Jorge Almeida

  73. FINITE SEMIGROUPS: AN INTRODUCTION TO A UNIFIED THEORY OF PSEUDOVARIETIES

    Article • November 2002, World Scientific Pub Co Pte Lt

    Jorge Almeida

  74. Article • Transactions of the American Mathematical Society, January 2002, American Mathematical Society (AMS)

    Jorge Almeida

  75. On the equation V∗G=EV

    Article • Journal of Pure and Applied Algebra, January 2002, Elsevier

    Jorge Almeida

  76. Some key problems on finite semigroups

    Article • Semigroup Forum, November 2001, Springer Science + Business Media

    Jorge Almeida

  77. SC-hyperdecidability of R

    Article • Theoretical Computer Science, March 2001, Elsevier

    Jorge Almeida

  78. GLOBALS OF PSEUDOVARIETIES OF COMMUTATIVE SEMIGROUPS: THE FINITE BASIS PROBLEM, DECIDABILITY AND GAPS

    Article • Proceedings of the Edinburgh Mathematical Society, February 2001, Cambridge University Press

    Jorge Almeida

  79. THE GAP BETWEEN PARTIAL AND FULL: AN ADDENDUM

    Article • International Journal of Algebra and Computation, February 2001, World Scientific Pub Co Pte Lt

    Jorge Almeida

  80. ON HYPERDECIDABLE PSEUDOVARIETIES OF SIMPLE SEMIGROUPS

    Article • International Journal of Algebra and Computation, April 2000, World Scientific Pub Co Pte Lt

    Jorge Almeida

  81. On finitely based pseudovarieties of the forms V∗D and V∗Dn

    Article • Journal of Pure and Applied Algebra, February 2000, Elsevier

    Jorge Almeida

  82. Syntactic and Global Semigroup Theory: A Synthesis Approach

    Article • January 2000, Springer Science + Business Media

    Jorge Almeida

  83. On the Decidability of Iterated Semidirect Products with Applications to Complexity

    Article • Test, January 2000, Oxford University Press (OUP)

    Jorge Almeida

  84. Article • Semigroup Forum, July 1999, Springer Science + Business Media

    Jorge Almeida

  85. HYPERDECIDABLE PSEUDOVARIETIES AND THE CALCULATION OF SEMIDIRECT PRODUCTS

    Article • International Journal of Algebra and Computation, June 1999, World Scientific Pub Co Pte Lt

    Jorge Almeida

  86. PSEUDOVARIETY JOINS INVOLVING ${\mathscr J}$ -TRIVIAL SEMIGROUPS

    Article • International Journal of Algebra and Computation, February 1999, World Scientific Pub Co Pte Lt

    Jorge Almeida

  87. The Gap Between Partial and Full

    Article • International Journal of Algebra and Computation, June 1998, World Scientific Pub Co Pte Lt

    Jorge Almeida

  88. On the hyperdecidability of semidirect products of pseudovarieties

    Article • Communications in Algebra, January 1998, Taylor & Francis

    Jorge Almeida

  89. Profinite categories and semidirect products

    Article • Journal of Pure and Applied Algebra, January 1998, Elsevier

    Jorge Almeida

  90. Free Profinite ℛ-Trivial Monoids

    Article • International Journal of Algebra and Computation, October 1997, World Scientific Pub Co Pte Lt

    Jorge Almeida

  91. Monoids Respectingn-Chains of Intervals

    Article • Journal of Algebra, January 1997, Elsevier

    Jorge Almeida

  92. The pseudovariety $J$ is hyperdecidable

    Article • RAIRO - Theoretical Informatics and Applications, January 1997, EDP Sciences

    Jorge Almeida

  93. Finite semigroups and universal algebra

    Article • Semigroup Forum, December 1996, Springer Science + Business Media

    Jorge Almeida

  94. Semigroups, automata and languages

    Article • Semigroup Forum, December 1996, Springer Science + Business Media

    Jorge Almeida

  95. A SYNTACTICAL PROOF OF LOCALITY OF DA

    Article • International Journal of Algebra and Computation, April 1996, World Scientific Pub Co Pte Lt

    Jorge Almeida

  96. Semigroups, Automata and Languages

    Article • March 1996, World Scientific Pub Co Pte Lt

    Jorge Almeida

  97. Finite Semigroups And Universal Algebra

    Article • January 1995, World Scientific Pub Co Pte Lt

    Jorge Almeida

  98. Finite Semigroups and Universal Algebra

    Article • January 1995, World Scientific Pub Co Pte Lt

    Jorge Almeida

  99. A Classification of Aperiodic Power Monoids

    Article • Journal of Algebra, December 1994, Elsevier

    Jorge Almeida

  100. REDUCED FACTORIZATIONS IN FREE PROFINITE GROUPS AND JOIN DECOMPOSITIONS OF PSEUDOVARIETIES

    Article • International Journal of Algebra and Computation, September 1994, World Scientific Pub Co Pte Lt

    Jorge Almeida

  101. A unified syntactical approach to theorems of Putcha, Margolis, and Straubing on finite power semigroups

    Article • Semigroup Forum, December 1993, Springer Science + Business Media

    Jorge Almeida

  102. Locally commutative power semigroups and counting factors of words

    Article • Theoretical Computer Science, February 1993, Elsevier

    Jorge Almeida

  103. Semigroups whose idempotents form a subsemigroup

    Article • Mathematical Proceedings of the Cambridge Philosophical Society, March 1992, Cambridge University Press

    Jorge Almeida

  104. On the membership problem for pseudovarieties of commutative semigroups

    Article • Semigroup Forum, December 1991, Springer Science + Business Media

    Jorge Almeida

  105. On iterated semidirect products of finite semilattices

    Article • Journal of Algebra, September 1991, Elsevier

    Jorge Almeida

  106. ON DIRECT PRODUCT DECOMPOSITIONS OF FINITE $\mathscr J$-TRIVIAL SEMIGROUPS

    Article • International Journal of Algebra and Computation, September 1991, World Scientific Pub Co Pte Lt

    Jorge Almeida

  107. On finite simple semigroups

    Article • Proceedings of the Edinburgh Mathematical Society, June 1991, Cambridge University Press

    Jorge Almeida

  108. Implicit operations on finite J-trivial semigroups and a conjecture of I. Simon

    Article • Journal of Pure and Applied Algebra, January 1991, Elsevier

    Jorge Almeida

  109. Demidirectly closed pseudovarieties of locally trivial semigroups

    Article • Semigroup Forum, December 1990, Springer Science + Business Media

    Jorge Almeida

  110. On pseudovarieties, varieties of languages, filters of congruences, pseudoidentities and related topics

    Article • Algebra Universalis, September 1990, Springer Science + Business Media

    Jorge Almeida

  111. Lattices, Semigroups, and Universal Algebra

    Article • January 1990, Springer Science + Business Media

    Jorge Almeida

  112. Semidirect products of pseudovarieties from the universal algebraist's point of view

    Article • Journal of Pure and Applied Algebra, October 1989, Elsevier

    Jorge Almeida

  113. The join of the pseudovarieties of R-trivial and L-trivial monoids

    Article • Journal of Pure and Applied Algebra, October 1989, Elsevier

    Jorge Almeida

  114. The algebra of implicit operations

    Article • Algebra Universalis, February 1989, Springer Science + Business Media

    Jorge Almeida

  115. On power varieties of semigroups

    Article • Journal of Algebra, January 1989, Elsevier

    Jorge Almeida

  116. Some pseudovariety joins involving the pseudovariety of finite groups

    Article • Semigroup Forum, December 1988, Springer Science + Business Media

    Jorge Almeida

  117. A notion of branching rank for semilattices with descending chain condition

    Article • Order, January 1988, Springer Science + Business Media

    Jorge Almeida

  118. On pseudovarieties of monoids

    Article • January 1988, Springer Science + Business Media

    Jorge Almeida

  119. Implicit Operations on Certain Classes of Semigroups

    Article • January 1987, Springer Science + Business Media

    Jorge Almeida

  120. Power pseudovarieties of semigroups II

    Article • Semigroup Forum, December 1986, Springer Science + Business Media

    Jorge Almeida

  121. Power pseudovarieties of semigroups I

    Article • Semigroup Forum, December 1986, Springer Science + Business Media

    Jorge Almeida

  122. Minimal nonpermutative pseudovarieties of semigroups. I

    Article • Pacific Journal of Mathematics, February 1986, Mathematical Sciences Publishers

    Jorge Almeida

  123. Minimal nonpermutative pseudovarieties of semigroups. II

    Article • Pacific Journal of Mathematics, February 1986, Mathematical Sciences Publishers

    Jorge Almeida

  124. Some order properties of the lattice of varieties of commutative semigroups

    Article • Canadian Journal of Mathematics, February 1986, Canadian Mathematical Society

    Jorge Almeida

  125. Some quasi-ordered classes of finite commutative semigroups

    Article • Semigroup Forum, December 1985, Springer Science + Business Media

    Jorge Almeida

  126. Minimal non-permutative pseudovarieties of semigroups III

    Article • Algebra Universalis, June 1985, Springer Science + Business Media

    Jorge Almeida

  127. Some algorithms on the star operation applied to finite languages

    Article • Semigroup Forum, December 1984, Springer Science + Business Media

    Jorge Almeida

  128. Generalized varieties of commutative and nilpotent semigroups

    Article • Semigroup Forum, December 1984, Springer Science + Business Media

    Jorge Almeida

  129. OVERLAPPING OF WORDS IN RATIONAL LANGUAGES

    Article • January 1983, Elsevier

    Jorge Almeida

  130. Equations for pseudovarieties

    Article • Springer Science + Business Media

    Jorge Almeida

  131. Profinite semigroups and applications

    Article • Springer Science + Business Media

    Jorge Almeida