Research articles of Valdis Laan
  1. V. Laan, On a generalization of strong flatness, Acta Comment. Univ. Tartuensis, no. 2 (1998), 55-60. (pdf)
  2. V. Laan, On classification of monoids by properties of cofree acts, Semigroup Forum, no. 59 (1999), 79-92.
  3. V. Laan, When torsion free acts are principally weakly flat, Semigroup Forum, no. 60 (2000), 321-325. (link)
  4. M. Kilp and V. Laan, On flatness properties of cyclic acts, Communications in Algebra, no. 28 (2000), 2919-2926.
  5. V. Laan, Pullbacks and flatness properties of acts I, Communications in Algebra, no. 29 (2) (2001), 829-850.
  6. S. Bulman-Fleming, M. Kilp and V. Laan, Pullbacks and flatness properties of acts II, Communications in Algebra, no. 29 (2) (2001), 851-878.
  7. S. Bulman-Fleming and V. Laan, Tensor products and preservation of limits, for acts over monoids, Semigroup Forum, no. 63 (2001), 161-179. (link)
  8. V. Laan, On Descent Theory for Monoid Actions, Applied Categorical Structures, no. 12 (5-6) (2004), 479-483.
  9. H. Oltmanns, U. Knauer, V. Laan and M. Kilp On (B,B)-projectivity, in: "Categorical Structures and their Applications. Proceedings of the North-West European Category Seminar, Berlin, Germany, 28-29 March 2003", World Scientific, Singapore, 2004, pp. 219-226.
  10. V. Laan, Wreath product of set-valued functors and tensor multiplication, Semigroup Forum, no. 70 (2005), 188-207. (link)
  11. S. Bulman-Fleming, V. Laan, Lazard's Theorem for S-posets, Math. Nachr., no. 278 (15) (2005), 1743-1755.
  12. X. Zhang, V. Laan, On homological classification of pomonoids by regular weak injectivity properties of S-posets, Cent. Eur. J. Math., no. 5(1) (2007), 181-200. Corrigendum.
  13. V. Laan, P. Penjam, On descent theory for distributors, Acta Comment. Univ. Tartuensis Math., no. 11 (2007), 13-22. (pdf)
  14. G. Janelidze, V. Laan, L. Márki, Limit preservation properties of the greatest semilattice functor, Internat. J. Algebra Comput., no. 18(5) (2008), 853-867.
  15. V. Laan, Generators in the category of S-posets, Cent. Eur. J. Math., no. 6(3) (2008), 357-363.
  16. V. Laan, Context equivalence of semigroups, Period. Math. Hung., no. 60(1) (2010), 81-94. (link)
  17. V. Laan, Tensor products and preservation of weighted limits, for S-posets, Comm. Algebra, no. 38(11) (2010), 4322-4332.
  18. V. Laan, L. Márki, Strong Morita equivalence of semigroups with local units, J. Pure Appl. Algebra, no. 215(10) (2011), 2538-2546.
  19. V. Laan, Morita theorems for partially ordered monoids, Proc. Est. Acad. Sci., no. 60(4) (2011), 221-237.
  20. V. Laan, L. Márki, Morita invariants for semigroups with local units, Monatsh. Math., no. 166(3) (2012), 441-451. DOI: 10.1007/s00605-010-0279-8.
  21. V. Laan, Acceptable Morita contexts for semigroups, ISRN Algebra, vol. 2012, article ID 725627, 2012, 5 pages. DOI:10.5402/2012/725627.
  22. T. Tärgla, V. Laan, Congruences of strongly Morita equivalent posemigroups, Acta Math. Univ. Comenian. (N.S.), no. 81(2) (2012), 247-254.
  23. M. Sedaghatjoo, V. Laan, M. Ershad Principal weak flatness and regularity of diagonal acts, Communications in Algebra, no. 40 (11) (2012), 4019-4030. DOI:10.1080/00927872.2011.600747
  24. V. Laan, Congruences of Morita equivalent small categories, Theory Appl. Categ., no. 26 (2012), 331-337. (pdf)
  25. V. Laan, On Morita equivalence of partially ordered monoids, Appl. Categ. Structures, no. 22 (2014), 137-146. DOI: 10.1007/s10485-013-9305-z
  26. X. Zhang, V. Laan, Injective hulls for posemigroups, Proc. Est. Acad. Sci., no. 63 (2014), 372-378. (pdf)
  27. V. Laan, N. Sohail, On mono- and epimorphisms in varieties of ordered algebras, Comm. Algebra., no. 43 (2015), 2802-2819. DOI:10.1080/00927872.2014.904328
  28. X. Zhang, V. Laan, On injective hulls of S-posets, Semigroup Forum, no. 91 (2015), 62-70. DOI: 10.1007/s00233-014-9646-4 .
  29. V. Laan, S. Nasir, L. Tart, On congruence extension properties for ordered algebras, Period. Math. Hung., no. 71 (2015), 92-111.
  30. X. Zhang, V. Laan, Quotients and subalgebras of sup-algebras, Proc. Est. Acad. Sci., no. 64 (2015), 311-322. (pdf)
  31. V. Laan, L. Márki, Fair semigroups and Morita equivalence, Semigroup Forum, no. 92 (2016), 633-644. DOI: 10.1007/s00233-015-9723-3. (link)
  32. X. Zhang, V. Laan, Injective hulls for ordered algebras, Algebra Universalis, no. 76 (2016), 339-349. DOI: 10.1007/s00012-016-0404-1. (link)
  33. V. Laan, N. Sohail, L. Tart, Hamiltonian ordered algebras and congruence extension, Math. Slovaca 67 (2017), 819-830.
  34. X. Liang, V. Laan, Y. Luo, R. Khosravi, Weakly torsion free S-posets, Comm. Algebra 45 (2017), 3340-3352. (pdf)
  35. V. Laan, L. Márki, Ü. Reimaa, Morita equivalence of semigroups revisited: firm semigroups, J. Algebra 505 (2018), 247-270.
  36. V. Laan, Ü. Reimaa, Monomorphisms in categories of firm acts, Studia Sci. Math. Hungar. 56 (2019), 267-279.
  37. V. Laan, Ü. Reimaa, Morita equivalence of factorizable semigroups, Internat. J. Algebra Comput. 29 (2019), 723-741.
  38. V. Laan, L. Márki, Ü. Reimaa, Lattices and quantales of ideals of semigroups and their preservation under Morita contexts, Algebra Univers. 81, 24 (2020). (link)
  39. V. Laan, K. Väljako, Enlargements of rings, Comm. Algebra 49 (2021), 1764-1772. (free e-print)
  40. Ü. Reimaa, V. Laan, L. Tart, Morita equivalence of finite semigroups, Semigroup Forum 102 (2021), 842-860. (pdf)
  41. V. Laan, Ü. Reimaa, L. Tart, E. Teor, Flatness properties of acts over semigroups, Categ. Gen. Algebr. Struct. Appl. 15 (2021), 59-92. (pdf)
  42. K. Väljako, V. Laan, Morita contexts and unitary ideals of rings, Proc. Est. Acad. Sci. 70 (2021), 122-134. (pdf)
  43. X. Zhang, V. Laan, J. Feng, Ü. Reimaa, Correction to: Injective hulls for ordered algebras, Algebra Universalis 82, 65 (2021). (link)
  44. X. Zhang, V. Laan, J. Feng, Injective hulls are completions of ordered algebras, Order, published online on August 03, 2023. (link)
  45. G. Kudryavtseva, V. Laan, Proper Ehresmann semigroups, Proc. Edinburgh Math. Soc. 66 (2023), 758-788. (link)
  46. V. Laan, A. Lepik, Perfection for semigroups, Proc. Edinburgh Math. Soc. 66 (2023), 259-287. DOI: 10.1017/S0013091523000159
  47. G. Kudryavtseva, V. Laan, Globalization of partial actions of semigroups, Semigroup Forum 107 (2023), 200-217. (link)
  48. V. Laan, J. Feng, X. Zhang, Admissible subsets and completions of ordered algebras, Algebra Universalis 84:19 (2023). DOI:10.1007/s00012-023-00813-9
  49. L. Marín, V. Laan, Firm homomorphisms of rings and semigroups, Theory Appl. Categ. 39 (2023), 625-666. (link)
  50. M. Kutti, V. Laan, Idempotent 2 × 2 matrices over linearly ordered abelian groups, Categ. Gen. Algebr. Struct. Appl. 21 (2024), 1-17. (link)
  51. V. Laan, K. Väljako, Enlargements and Morita contexts for rings with involution, Glasg. Math. J., published online 25.11.2024. (link)
  52. M. Kutti, V. Laan, Green's relations for 2x2 matrices over linearly ordered abelian groups, to appear in Proc. Est. Acad. Sci.
  53. Ü. Reimaa, V. Laan, L. Tart, U-fair semigroups and the firmification of acts, submitted.
  54. V. Laan, Enlargements and Morita contexts for semirings, submitted.
My PhD thesis can be found here.

If you wish to have an electronic copy of any of these articles, please send an e-mail to: valdis dot laan at ut dot ee .