Abstract
Working in an arbitrary category endowed with a fixed \(({\mathcal {E}}, {\mathcal {M}})\)-factorization system such that \({\mathcal {M}}\) is a fixed class of monomorphisms, we first define and study a concept of codense morphisms with respect to a given categorical interior operator i. Some basic properties of these morphisms are discussed. In particular, it is shown that i-codenseness is preserved under both images and dual images under morphisms in \({\mathcal {M}}\) and \({\mathcal {E}}\), respectively. We then introduce and investigate a notion of quasi-open morphisms with respect to i. Notably, we obtain a characterization of quasi i-open morphisms in terms of i-codense subobjects. Furthermore, we prove that these morphisms are a generalization of the i-open morphisms that are introduced by Castellini. We show that every morphism which is both i-codense and quasi i-open is actually i-open. Examples in topology and algebra are also provided.
Similar content being viewed by others
References
Adámek, J., Herrlich, H., Strecker, G.: Abstract and Concrete Categories. Pure and Applied Mathematics. Wiley, New York (1990)
Assfaw, F.: Interior Operators and Their Applications. Ph.D. thesis, University of the Western Cape (2019)
Assfaw, F., Holgate, D.: Hereditary Interior Operators. Submitted for publication (2019)
Castellini, G.: Categorical Closure Operators. Mathematics: Theory & Applications. Birkhäuser Boston, Inc., Boston (2003)
Castellini, G.: Interior operators in a category: idempotency and heredity. Topol. Appl. 158(17), 2332–2339 (2011)
Castellini, G.: Interior operators, open morphisms and the preservation property. Appl. Categ. Struct. 23(3), 311–322 (2015)
Castellini, G.: Some remarks on interior operators and the functional property. Quaest. Math. 39(2), 275–287 (2016)
Castellini, G., Murcia, E.: Interior operators and topological separation. Topol. Appl. 160(12), 1476–1485 (2013)
Castellini, G., Ramos, J.: Interior operators and topological connectedness. Quaest. Math. 33(3), 290–304 (2010)
Clementino, M., Giuli, E., Tholen, W.: A functional approach to general topology. In: Categorical Foundations, Volume 97 of Encyclopedia of Mathematics and Applications., pp. 103–163. Cambridge University Press, Cambridge (2004)
Dikranjan, D., Giuli, E.: Closure operators. I. In: Proceedings of the 8th International Conference on Categorical Topology (L’Aquila, 1986), vol. 27, pp. 129–143 (1987)
Dikranjan, D., Giuli, E., Tholen, W.: Closure operators. II. Categorical Topology and Its Relation to Analysis. Algebra and Combinatorics (Prague, 1988), pp. 297–335. World Scientific Publishing, Teaneck (1989)
Dikranjan, D., Tholen, W.: Categorical Structure of Closure Operators. Mathematics and its Applications, vol. 346. Kluwer Academic Publishers Group, Dordrecht (1995)
Dikranjan, D., Tholen, W.: Dual closure operators and their applications. J. Algebra 439, 373–416 (2015)
Engelking, R.: General Topology, Volume 6 of Sigma Series in Pure Mathematics, 2nd edn. Heldermann Verlag, Berlin (1989)
Herrlich, H., Strecker, G.E.: \(H\)-closed spaces and reflective subcategories. Math. Ann. 177, 302–309 (1968)
Holgate, D., Šlapal, J.: Categorical neighborhood operators. Topol. Appl. 158(17), 2356–2365 (2011)
Kao, K.S.: A note on \(M_{1}\)-spaces. Pac. J. Math. 108(1), 121–128 (1983)
Kim, J.W.: A note on quasi-open maps. J. Korea Soc. Math. Educ. Ser. B Pure Appl. Math. 5(1), 1–3 (1998)
Luna-Torres, J., Ochoa, C.O.C.: Interior operators and topological categories. Adv. Appl. Math. Sci. 10(2), 189–206 (2011)
Mardešić, S., Papić, P.: Continuous images of ordered compacta, the Suslin property and diadic compacta. Glasnik Mat.-Fiz. Astronom. Drukštvo Mat. Fiz. Hrvatske SER. II 17, 3–25 (1963). 1962
Razafindrakoto, A., Holgate, D.: Interior and neighbourhood. Topol. Appl. 168, 144–152 (2014)
Salbany, S.: Reflective Subcategories and Closure Operators, pp. 548–565. Lecture Notes in Mathematics, vol. 540 (1976)
Vorster, S.: Interior operators in general categories. Quaest. Math. 23(4), 405–416 (2000)
Acknowledgements
Our sincere thanks go to both the editor and the anonymous referee for their generous work and precious comments that significantly improved the exposition of the paper.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Maria Manuel Clementino.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Assfaw, F.S., Holgate, D. Codenseness and Openness with Respect to an Interior Operator. Appl Categor Struct 29, 235–248 (2021). https://doi.org/10.1007/s10485-020-09614-w
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10485-020-09614-w