Preprints                        Publications                        Editions                        Google Scholar

Preprints


On toposes, algebraic theories, semi-abelian categories and compact Hausdorff spaces (with Francis Borceux)
Preprint  24-12, DMUC.

 Abstract: In this paper we study the categories (C*)^op and ((C*)^op)^T of T-models in (C*)^op for an arbitrary algebraic theory T, when C is a topos or the category CHaus of compact Hausdorff spaces. It is well-known that, when C is a topos, (C*)^op is semi-abelian. We show that (CHaus*)^op is semi-abelian, as well as ((CHaus*)^op)^T, and that, when C is a topos having locales of subobjects, ((C*)^op)^T is also semi-abelian. In addition, we prove the representability of actions in (CHaus*)^op.


Effective descent morphisms of filtered preorders (with George Janelidze)
Preprint  23-37, DMUC. arXiv 2312.14315

 Abstract: We characterize effective descent morphisms of what we call filtered preorders, and apply these results to slightly improve a known result, due to the first author and F. Lucatelli Nunes, on the effective descent morphisms in lax comma categories of preorders. A filtered preorder, over a fixed preorder X, is defined as a preorder A equipped with a profunctor X-> A and, equivalently, as a set A equipped with a family (A_x)_{x\in X} of upclosed subsets of A with x' \leq x => A_x\subseteq A_x'.

A note on Mal'tsev objects (with Diana Rodelo)
Preprint  23-36, DMUC. arXiv 2311.17628

 Abstract: The aim of this work is to compare the distinct notions of Mal'tsev object in the sense of Weighill and in the sense of Montoli-Rodelo-Van der Linden.


Publications


 F. Borceux, M. M. Clementino, On coherent systems of subobjects with application to torsion theory. Theory Appl. Categ. (to appear). Preprint  22-33, DMUC. arXiv 2210.14337

M. M. Clementino, F. Lucatelli Nunes, Lax comma 2-categories and admissible 2-functors. Theory Appl. Categ. (to appear). Preprint  20-06, DMUC. arXiv 2002.03132

M. M. Clementino, F. Lucatelli Nunes, Lax comma categories of ordered sets. Quaestiones Mathematicae 46 (S1) (2023) 145-159. Preprint  22-49, DMUC. arXiv 2212.13541

M.M. Clementino, C. Ruivo, On split extensions of preordered groups. Port. Math. 80 (2023) 327-341. Preprint  22-40, DMUC. arXiv 2212.07064

M.M. Clementino, A. Montoli, D. Rodelo, On lax protomodularity for Ord-enriched categories. J. Pure Appl. Algebra 227, Issue 8 (2023) 107348. Preprint  22-22, DMUC. arXiv 2210.14332

M.M. Clementino, C. Fitas,  On presheaf submonads of quantale enriched categories. Quaestiones Mathematicae 46 (10) (2023) 2079-2108. Preprint  22-02, DMUC. arXiv 2202.06805

M.M. Clementino, An invitation to topological semi-abelian algebras. In: New perspectives in Algebra, Topology and Categories, Coimbra Mathematical Texts, Vol. 1, Springer Nature and University of Coimbra (2021), pp. 27-66.
 
M.M. Clementino, (T,V)-Cat is extensive. Theory Appl. Categ. 36, nº 14 (2021), 368-378. Preprint 21-18, DMUC.

M.M. Clementino, A. Montoli, On the categorical behaviour of V-groups. J. Pure Appl. Algebra 225 (2021) 106550. Preprint  20-18, DMUC. arXiv 2005.07738
F. Borceux, M.M. Clementino, On bornological semi-abelian algebras. Categ. Gen. Algebr. Struct. Appl. 14 (2021) 181-222. Preprint 19-34, DMUC.

M.M. Clementino, I. López Franco, Lax orthogonal factorisations in ordered structures. Theory Appl. Categ. 35, nº 36 (2020) 1379-1423. Preprint  17-06, DMUC. arXiv 1702.02602

 M.M. Clementino, D. Hofmann, W. Ribeiro, Cartesian closed exact completions in topology. J. Pure Appl. Algebra 224 (2020) 610-629. Preprint  18-46, DMUC. arXiv 1811.03993. DOI: 10.1016/j.jpaa.2019.06.003

M.M. Clementino, G. Janelidze, Another note on effective descent morphisms of topological spaces and relational algebras. Topology Appl. 273 (2020), 106961. Preprint  18-32, DMUC.

F. Cagliari, M.M. Clementino, Topological groups have representable actions. Bulletin of the Belgium Math. Society -- Simon Stevin 26 (2019), 519-526. Preprint  18-29, DMUC.

M.M. Clementino, N. Martins-Ferreira, A. Montoli, On the categorical behaviour of preordered groups. J. Pure Appl. Algebra 223 (2019), 4226-4245. Preprint  18-22, DMUC. DOI: 10.1016/j.jpaa.2019.01.006

M.M. Clementino, J. Picado, A. Pultr, The other closure and complete sublocales. Appl. Categ. Structures 26 (2018), 891-906. Preprint  17-40, DMUC. DOI: 10.1007/s10485-018-9516-4

M.M. Clementino, M. Gran, G. Janelidze, Some remarks on protolocalizations and proto-additive reflections. J. Algebra Appl., Volume 17, Number 11 (2018), 1850207. DOI: 10.1142/S0219498818502079. Preprint  17-13, DMUC. arXiv 1702.08822

M.M. Clementino, Ignacio López Franco, Lax orthogonal factorisations in quantale-monad-enriched categories. Logical Methods in Computer Science Vol. 13 (3:32) 2017, pp. 1–16. Preprint  17-03, DMUC. arXiv 1701.05510

M.M. Clementino, D. Hofmann, The rise and fall of V-functors, Fuzzy Sets and Systems 321 (2017) 29-49. Preprint  16-06, DMUC.

M.M. Clementino, Ignacio López Franco, Lax orthogonal factorisation systems. Adv. Math. 302 (2016) 458-528. Preprint  15-09, DMUC; arXiv 1503.06469

M.M. Clementino, D. Hofmann, G. Janelidze, On exponentiable morphisms in classical algebras. Appl. Categ. Structures 24 (2016) 733-742. Preprint  15-56, DMUC

F. Cagliari, M.M. Clementino, S. Mantovani, Fibrewise injectivity in order and topology. Topology Appl. 200 (2016) 61-78. Preprint  14-20, DMUC

D. Chikhladze, M.M. Clementino, D. Hofmann, Representable (T,V)-categories. Appl. Categ. Structures 23 (2015) 829-858. Preprint  12-47, DMUC

M.M. Clementino, A. Montoli, L. Sousa, Semidirect products of (topological) semi-abelian algebras. J. Pure Appl. Algebra 219 (2015) 183-197. Preprint 13-47, DMUC

F. Borceux, M.M. Clementino, A. Montoli, On the representability of actions for topological algebras. In: Categorical Methods in Algebra and Topology, Textos de Matemática, DMUC, Vol. 46 (2014) 41-66. Preprint  14-19, DMUC

 M.M. Clementino, W. Tholen, From lax monad extensions to Topological theories. In: Categorical Methods in Algebra and Topology, Textos de Matemática, DMUC, Vol. 46 (2014) 99-123. Preprint  14-39, DMUC

M.M. Clementino, D. Hofmann, A. Montoli, Covering morphisms in categories of relational algebras. Appl. Categ. Structures 22 (2014) 767-788. Preprint 12-45, DMUC

M.M. Clementino, E. Colebunders, W. Tholen, Lax Algebras as Spaces. In: Monoidal Topology. A Categorical Approach to Order, Metric and Topology, Encyclopedia Math. Appl. 153, Cambridge Univ. Press (2014), pp. 375-465: contents

M.M. Clementino, D. Hofmann, G. Janelidze, The monads of classical algebra are seldom weakly cartesian. J. Homotopy Relat. Struct. 9 (2014) 175-197. Preprint 12-46, DMUC

F. Cagliari, M.M. Clementino, S. Mantovani, Fibrewise complete posets and continuous lattices. In: Recent Progress for Topology, Computer Science, Fuzzy Mathematics and Economics, Univ. of the Basque Country, Bilbao (2013), pp. 69-75.

M.M. Clementino, D. Hofmann, G. Janelidze, On exponentiability of étale algebraic homomorphisms. J. Pure Appl. Algebra 217 (2103) 1195-1207. Preprint 11-35, DMUC.

M.M. Clementino, W. Tholen, Proper maps for lax algebras and the Kuratowski-Mrówka Theorem. Theory Appl. Categ. 27 (2012) 327-346. Preprint 12-16, DMUC
F. Cagliari, M.M. Clementino, S. Mantovani, Fibrewise injectivity and Kock-Z"oberlein monads. J. Pure Appl. Algebra 216 (2012) 2411-2424. Preprint 11-32, DMUC

M.M. Clementino, D. Hofmann, Descent morphisms and a van Kampen Theorem in categories of lax algebras. Topology Appl. 159 (2012) 2310-2319. Preprint 11-01, DMUC

M.M. Clementino, G. Janelidze, A note on effective descent morphisms of topological spaces and relational algebras. Topology Appl. 158 (2011) 2431-2436. Preprint 10-55, DMUC

M.M. Clementino, D. Hofmann, On the completion monad via the Yoneda embedding in quasi-uniform spaces. Topology Appl. 158 (2011) 2423-2430. Preprint 10-46, DMUC

M.M. Clementino, A note on the categorical van Kampen Theorem. Topology Appl. 158 (2011) 926-929. Preprint 10-45, DMUC

M.M. Clementino, G. Gutierres, On regular and homological closure operators. Cah. Topol. Géom. Différ. Catég. LI (2010) 127-142. Preprint 09-49, DMUC

A. Akhvlediani, M.M. Clementino, W. Tholen, On the categorical meaning of Hausdorff and Gromov distances, I. Topology Appl. 157 (2010) 1275-1295. Preprint 09-01, DMUC    

M.M. Clementino, D. Hofmann, Lawvere completeness in topology. Appl. Categ. Structures 17 (2009) 175-210.

M.M. Clementino, D. Hofmann, I. Stubbe, Exponentiable functors between quantaloid-enriched categories. Appl. Categ. Structures 17 (2009) 91-101. Preprint 06-50, DMUC

M.M. Clementino, D. Hofmann, Relative injectivity as cocompleteness for a class of distributors. Theory Appl. Categ. 21 (2008) 210-230.

F. Borceux, M.M. Clementino, M. Gran, L. Sousa, Protolocalisations of homological categories. J. Pure Appl. Algebra 212 (2008) 1898–1927. Preprint 06-60, DMUC

M.M. Clementino, D. Hofmann, On some special classes of continuous maps. Chapter 39, Part 4, of  Open Problems in Topology 2, pages 367-376, edited by Elliott Pearl, Elsevier 2007. Preprint 06-37, DMUC

M.M. Clementino, Towards categorical behaviour of groups, CIM Bulletin 23 (2007), 7-12.

M.M. Clementino, D. Dikranjan, W. Tholen, Torsion theories and radicals  in normal categories. J. Algebra 305 (2006) 98-129. Preprint 05-19, DMUC

F. Borceux, M.M. Clementino, Topological protomodular algebras. Topology Appl. 153 (2006) 3085-3100. Preprint 04-10, DMUC

M.M. Clementino, D. Hofmann, Exponentiation in V-categories. Topology Appl. 153 (2006) 3113-3128.

F. Borceux, M.M. Clementino, Topological semi-abelian algebras. Adv. Math. 190 (2005) 425-453.

M.M. Clementino, D. Hofmann, G. Janelidze, Local homeomorphisms via ultrafilter convergence. Proc. Amer. Math. Soc. 133 (2005) 917-922.

M.M. Clementino, D. Hofmann, Effective descent morphisms in categories of lax algebras. Appl. Categ. Structures 12 (2004) 413-425. Preprint 02-20, DMUC

M.M. Clementino, D. Hofmann, On extensions of lax monads. Theory Appl. Categ. 13 (2004) 41-60.

M.M. Clementino, D. Hofmann, Walter Tholen, One setting for all: metric, topology, uniformity, approach structure. Appl. Categ. Structures 12 (2004) 127-154.

M.M. Clementino, E. Giuli, W. Tholen, A Functional Approach to General Topology. In: Categorical Foundations. Special Topics in Order, Topology, Algebra, and Sheaf Theory, Encyclopedia Math. Appl. 97, CUP (2004), pp. 103-163.

M.M. Clementino, D. Hofmann, Walter Tholen, Exponentiability in categories of lax algebras. Theory Appl. Categ. 11 (2003) 337-352.

M.M. Clementino, W. Tholen, Metric, Topology and Multicategory - A Common Approach. J. Pure Appl. Algebra 179 (2003) 13-47.

M.M. Clementino, D. Hofmann, Topological features of lax algebras. Appl. Categ. Structures 11 (2003) 267-286.

M.M. Clementino, D. Hofmann, Walter Tholen, The convergence approach to exponentiable maps. Port. Math. (N.S.) 60 (2003) 139-160.

M.M. Clementino, D. Hofmann, On limit stability of special classes of continuous maps. Topology Appl. 125 (2002) 471-488.

M.M. Clementino, D. Hofmann, Triquotient maps via ultrafilter convergence. Proc. Amer. Math. Soc. 130 (2002) 3423-3431.

M.M. Clementino, On finite triquotient maps. J. Pure Appl. Algebra 168 (2002) 387-389.

M.M. Clementino, W. Tholen, A note on local compactness. Rend. Ist. Mat. Univ. Trieste, Suppl. 2, XXXII (2001) 17-31.

M.M. Clementino, On connectedness via closure operators. Appl. Categ. Structures 9 (2001) 539-556.

M.M. Clementino, E. Giuli, W. Tholen, What is a quotient map with respect to a closure operator? Appl. Categ. Structures 9 (2001) 139-151.

M.M. Clementino, W. Tholen, Separated and connected maps. Appl. Categ. Structures 6 (1998) 373-401.

M.M. Clementino, W. Tholen, A Characterization of the Vietoris Topology. Topology Proc. 22 (1997) 71-95.

M.M. Clementino, W. Tholen, Separation versus connectedness. Topol. Appl. 75 (1997) 143-181.

M.M. Clementino, W. Tholen, Tychonoff's Theorem in a Category. Proc. Amer. Math. Soc. 124 (1996) 3311-3314.

M.M. Clementino, E. Giuli, W. Tholen, Topology in a Category: Compactness. Port. Math. (N.S.) 53 (1996) 397-433.

M.M. Clementino, On categorical notions of compact object. Appl. Categ. Structures 4 (1996) 15-29.

M.M. Clementino, Constant morphisms and constant subcategories. Appl. Categ. Structures 3 (1995) 119-137.

M.M. Clementino, On connectedness and disconnectedness. In: Topology with Applications (Szekszard, Hungary, 1993), Math. Studies 4 (Bolyai Soc.), pgs. 71-82.

M.M. Clementino, Weakly hereditary regular closure operators. Topology Appl. 49 (1993) 129-139.

M.M. Clementino, Hausdorff separation in categories. Appl. Categ. Structures 1 (1993) 285-295.

M.M. Clementino, T0- and T1-reflections. Comment. Math. Univ. Carolin. 33 (1992) 493-504.


Editions
                                Applied Categorical Structures
                               Cahiers de Topologie et Géométrie Différentielle Catégoriques                              
                               Categories and General Algebraic Structures with Applications
                      Portugaliae Mathematica
                          Theory and Applications of Categories



Theory and Applications of Categories 40 (2024).
A special volume celebrating Marta Bunge's contributions to category theory.
Editors: Maria Manuel Clementino, Valeria de Paiva, Jonathon Funk.

New Perspectives in Algebra, Topology and Categories
Coimbra Mathematical Texts, Vol 1, Springer Nature and University of Coimbra (2021)
Editors: Maria Manuel Clementino, Alberto Facchini, Marino Gran.

Topology and its Applications (2020).
Special volume, dedicated to Ale\v s Pultr on the occasion of his eightieth birthday.
Foreword, Topology and its Applications 273 (2020), 106959.
Editors: Bernhard Banaschewski, Maria Manuel Clementino, Jorge Picado.

Applied Categorical Structures 26 (5) (2018).
Volume dedicated to Robert Lowen.
Editors: Bernhard Banaschewski, Maria Manuel Clementino, Eva Colebunders, George Janelidze, Ross Street, Walter Tholen.

Journal of Homotopy and Related Structures 11 (4) (2016).
Volume dedicated to the 80th birthday of Ronnie Brown.
Editors: Maria Manuel Clementino, Marino Gran, George Janelidze, Tim Porter.

Tbilisi Mathematical Journal 8 (1) (2015).
Volume dedicated to the 70th birthday of Marco Grandis.
Editors: Maria Manuel Clementino, Marino Gran, George Janelidze, Robert Paré.

Textos de Matemática, Série B, Volume 46, DMUC (2014).
Volume dedicated to the 70th birthday of Manuela Sobral.
Editors: Maria Manuel Clementino, George Janelidze, Jorge Picado, Lurdes Sousa, Walter Tholen.

Applied Categorical Structures 22 (5-6) (2014).
Volume dedicated to the 60th birthday of George Janelidze.
Editors: Maria Manuel Clementino, Marino Gran, Manuela Sobral, Ross Street, Walter Tholen.

Topology and its Applications 158 (17) (2011).
Volume dedicated to the 70th birthday of Eraldo Giuli.
Editors: Maria Manuel Clementino, Jorge Picado, Walter Tholen.

Applied Categorical Structures 17 (3-4) and 18 (2-3), 2009-10. Dedicated to:
Proceedings of the International Conference on Category Theory 2007, CT07, Carvoeiro, Portugal.
Editors: Samson Abramsky, Maria Manuel Clementino, Ross Street.

Theory and Applications of Categories 21 (2008).
The Tholen Festschrift, A special volume dedicated to Walter Tholen on the occasion of his 60th birthday.
Editors: Maria Manuel Clementino, George Janelidze, Robert Rosebrugh, Jirí Rosický.

Topology and its Applications 137 (1-3) (2004).
Volume dedicated to the Proceedings of the IV Ibero-American Conference on Topology and its Applications, 2001.
Editors: Ofelia T. Alas, Maria Manuel Clementino, Jerry Vaughan.

CMUC, 2002: da Matemática, faces por dobrar; An interview with Jeremy J. Gray; An interview with David B. A. Epstein; An interview with Friedrich Hirsebruch; An interview with Gregory J. Chaitin.
Editors: Francisco Craveiro de Carvalho, Paula de Oliveira, Maria Manuel Clementino.

Textos de Matemática, Série B, 21, DMUC (1999).
School on Category Theory and Applications.
Editors: Manuela Sobral, Maria Manuel Clementino, Jorge Picado, Lurdes Sousa.

Our Speaker Today, DMUC, 1999.
Editors: Francisco Craveiro de Carvalho, Maria Manuel Clementino, Sofia Gonçalves Pereira, Carlos Leal.