Publication list
Publication list
Book publications
A) Algebra
- Algebraic Graph Theory - Morphisms, Monoids and Matrices 2nd edition (with Kolja Knauer) De Gruyter, Berlin and Boston 2019
- Monoids, Acts and Categories De Gruyter Expositions in Mathematics Reprint CIP 2016 (PR China)(with Mati Kilp and Alexander V. Mikhalev)
- Discrete and algebraic structures - in brief, 2nd edition, Springer Spektrum, Berlin Heidelberg 2015 (with Kolja Knauer)
- Algebraic Graph Theory - Morphisms, Monoids and Matrices De Gruyter, Berlin 2011
- Graph Asymmetries, Special Issue Discrete Mathematics 309 (2009) 5349 - 5424 Edited by Roland Kaschek and Ulrich Knauer
- Workshop on Graph Asymmetries Electronic Notes in Discrete Mathematics Volume 23, Pages 1-60 Edited by Roland Kaschek and Ulrich Knauer
- Discrete Structures - in Brief Spektrum Verlag, Heidelberg 2001
- Monoids, Acts and Categories with applications to wreath products and graphs, A Handbook for Students and Researchers W. de Gruyter Expositions in Mathematics, Vol. 29, Berlin et al. 2000 (with M. Kilp and A.V. Mikhalev)
- First International Taiwan-Moscow Algebra Workshop, W. de Gruyter, Berlin et al. 1996 (ed. with Y. Fong and A.V. Mikhalev)
B) Modelling and professional practice
- Light rail for Hamburg, study, Verein Pro-Stadtbahn-Hamburg.e.V., Hamburg, June 2014 (with Dieter Doege)
- RE 2 Study - Back to punctuality, IHK Cottbus and ProBahn Berlin/Brandenburg (ed.), Cottbus, January 2014 (with Dieter Doege)
- Materialien zur Entstehung der Mathematischen Berufe Daten aus Hochschulstatistiken sowie Volks- und Berufszählungen von 1800 bis 1990 Algorismus, Heft 12, Institute of History of Natural Sciences, Munich 1994 (with M. Böttcher and H.E. Groß)
- Mathematische Modelle Laster, Busse und Schweine im Mathematikstudium Vieweg, Braunschweig, Wiesbaden, 1992 Mathematik und Lehrerberuf DVV, Bonn 1978 (with G. Becker, J. Maass, V. Reiß)
Articles in journals and edited volumes
A.) Algebra and graph theory
72. | A formula for the number of weak endomorphisms of paths, Algebra and Discrete Mathematics, 26 (2018) 2, pp. 270-279 (with Nirutt Pipattanajinda), |
71. | The Endomorphism Monoids of (n - 3)-regular Graphs of Order n, Algebra and Discrete Mathematics, 22 (2016) 2 (with Boyko Gyurov, Sayan Panma and Nirutt Pipattanajinda) |
70. | On planar right groups Semigroup Forum 92(1)(2016), 142--157 (with K. Knauer) |
69. | Completely regular endomorphisms of split graphs Ars Combinatoria 115(2014), 367 - 384 (with A. Wanichsombat) |
68. | The endomorphism monoids of graphs of order n with minimum degree n-3. Algebra and Discrete Mathematics, 2 (2014) 274 - 294. (with Boyko Gyurov, Sayan Panma and Nirutt Pipattanajinda) |
67. | A characterisation of a pomonoid all of its cyclic S-posets are regular injective, Categories and General Algebraic Structures with Applications, 1 (1), December 2013, 103 - 116 (with Xia Zhang, Wenling Zhang) |
66. | Endo-regularity of Generalised Wheel Graphs Chamchuri Journal of Mathematics 3 (2011) 45 - 57 (with Nirutt Pipattanajinda and Srichan Arworn) |
65. | On endomorphism monoids of Clifford semigroups Preprint 2011 (with P. Puusemp and S. Woraswiset) |
64. | Characterisations of completely simple semigroup digraphs Algebra and Discrete Mathematics 12 (2011) 53 - 69 (with J. Meksawang and S. Panma) |
63. | Toroidal embeddings of right groups Thai J. Math 8 (2010) 483 - 490 (with K. Knauer) |
62. | Orthodox endomorphism monoids of strong semilattices of semigroups Preprint 2009 (with S. Worawiset) |
61. | Regular endomorphism monoids of Clifford semigroups Preprint 2009 (with S. Worawiset) |
60. | The Congruence Classes of Paths and Cycles Discrete Math. 309 (2009) 5352 - 5359 (with Martin A. Michels) |
59. | On Transitive Cayley Graphs of Strong Semilattices of Right (Left) Groups Discrete Math. 309 (2009) 5393 - 5403 (with S. Panma and Sr. Arworn) |
58. | Classification of monoids by injectivities II. CC-injectivity, Semigroup Forum 76 (2008) 177 - 184 (with X. Zhang, Y.Chen) |
57. | Classification of monoids by injectivities I. C-injectivity, Semigroup Forum 76 (2008) 169 - 176 (with X. Zhang, Y. Chen) |
56. | Various notions of weak injectivity over Clifford semigroups, Semigroup Forum 76 2008, 357-367 (with X. Zhang, Y. Wang) |
55. | Functorial Properties of Cayley Constructions Acta Comment. Univ. Tartu Mathematica, 10 (2006) 17-29 (with X. Zhang, Y. Wang) |
54. | Locally Strong Enomorphisms of Paths Discr. Math. 308 (2008) 2525 - 2532 (with Sr. Arworn and S. Leeratanavalee) |
53. | Characterisation of Clifford semigroup digraphs Discrete Mathematics, 306 (2006) 1247-1252 (with S. Panma, N. N. Chiangmai and Sr. Arworn) |
52. | On weakly projective amalgams Communication in Algebra 33 (2005), 1147-1151 (with M. Kilp) |
51. | On Rees weakly projective right acts Fundamental and applied Mathematics 10 (2004) 85-96 (in Russian) (with H. Oltmanns) |
50. | On transitive Cayley graphs of right (left) groups and of Clifford semigroups Thai Journal of Mathematics, 2 (2004) 1, 183-195 (with S. Panma and Sr. Arworn) |
49. | On (B,B)-projectivity in: W. Gähler, G. Preuss (eds.), Categorical Structures and their Applications, 219-226, World Scientific, New Jersey,2004, (with H. Oltmanns, V. Laan, M. Kilp) |
48. | Characterisation of Digraphs of Right (Left) Zero Unions of Groups Thai Journal of Mathematics 1 (2003) 131-140 (with Sr. Arworn and N. N. Chiangmai) |
47. | Postscript: "Endomorphism spectra of graphs" [Discrete Mathematics 109 (1992) 45-57] Discrete math. 270 (2003), 329-331 (with M. Böttcher) |
46. | Graph operations and categorical constructions Acta Comment. Univ. Tartu. Mathematica 5 (2001), 43-57 (with M. Kilp) |
45. | On Torsionless and Dense Acts Semigroup Forum 63 (2001) 396 - 414 (with M. Kilp) |
44. | Divisible, Torsion-Free and Act Regular Generalised Act Wreath Products J. Algebra 241 (2001) 592 - 610 |
43. | Non additive Morita Theory. A survey in: Algebra, Proceedings of the Kurosh Conference, Moskva 1998, 167-180, W. de Gruyter, Berlin 2000 |
42. | Weak projectivities for S-acts in: K.Denecke, H.J. Vogel (eds.): General Algebra and Discrete Mathematics, 143-159, Aachen 1999 (with H. Oltmanns) |
41. | Semigroups with generalised polynomial identities in: Y. Fong, U. Knauer, A.V. Mikhalev (eds.): First International Taiwan-Moscow Algebra Workshop, 147-157 W. de Gruyter, Berlin et al. 1996 (with K.I. Beidar, Y. Fong, A.V. Mikhalev, K.P. Shum) |
40. | PP-Endomorphism monoids of free acts in: I. Almeida et al. (eds.): Semigroups, Automata and Languages (Porto 1994) 101 - 109, World Scientific, Singapore et al. 1996 (with V. Fleischer) |
39. | Antiisomorphisms of operator semigroups of p-adic Banach spaces in: Mathematical models and methods in social science, 69-71, Sbornik MGSU, 1994 (Russian) (with A.V. Mikhalev, L.I. Mikhaleva) |
38. | An example of two von Neumann regular rings with non-isomorphic Morita equivalent multiplicaive monoids Semigroup Forum, 48 (1994), 381-383 (with K. Beidar, A.V. Mikhalev) |
37. | Wreath products of monoids with small categories whose principal onesided ideals form chains SEA Bull. Math 18 (1994) 63-72 (with V. Fleischer) |
36. | Endomorphism spectra of bipartite graphs in: M. Ito, H. Jürgensen (eds.): Words, Languages, Combinatorics II, (Kyoto 1992) 234-251, World Scientific Singapore 1994. |
35. | Wreath products of monoids with small categories whose principal onesided ideals form trees J. Algebra, 170 (1994), 69 - 100 (with V. Fleischer) |
34. | Endomorphism monoids of generators in the category of acts over monoids in: J.M. Howie, W.D. Munn, H.J. Weinert (eds.), Semigroups and Applications, 132-151, World Scientific Publ., Singapore 1992 (with A.V. Mikhalev) |
33. | Characterisation of monoids by properties of generators Communications Alg., 20 (7) (1992), 1841-1856 (with M. Kilp) |
32. | Endomorphism spectra of graphs Discr. Math. 109 (1992), 45-47 (with M. Böttcher) |
31. | Endomorphism types of trees in: M. Ito (ed.), Words, Languages, Combinatorics, World Scientific Publ., Singapore et al., 1992, 273-287 |
30. | Das Endomorphismen Spektrum eines Graphen Reprint series of the Pädagogische Hochschule Güstrow, Algebra und Grenzgebiete, Güstrow 1991, 51-55 |
29. | Hereditary endomorphism monoids of projective acts Manuscripta math. 70 (1991), 133-143 (with P. Normak) |
28. | Endomorphisms of graphs II. Various unretractive graphs Arch. Math., 55 (1990), 193-203 |
27. | Morita duality for monoids Semigroup Forum, 40 (1990), 39-57 (with P. Normak) |
26. | Endomorphisms of graphs I. The monoid of strong endomorphisms Arch. Math, 52 (1989), 607-614 (with M. Nieporte) |
25. | Wreath products of acts over monoids II. Torsion free and divisible acts J. Pure Appl. Alg., 58 (1989), 19-27 (with M. Kilp and A. V. Mikhalev) |
24. | Wreath products of acts over monoids I. Regular and inverse acts J. Pure Appl. Alg., 51 (1988), 251-260 (with A. V. Mikhalev) |
23. | Endomorphism monoids of acts are wreath products of monoids with small categories in: Lecture Notes in Mathematics 1320, Springer, Berlin u.a. 1988, 84-96 (with V. Fleischer) |
22. | Characterisation of monoids by properties of faithful and strongly faithful acts Acta Comment. Univ. Tartu. 764 (1987), 39-48 (with M. Kilp) |
21. | Unretractive and S-unretractive joins and lexicographic products of graphs J. Graph Theory, 11 (1987), 429-440 |
20. | Characterisation of monoids by properties of regular acts J. Pure Appl. Alg., 46 (1987), 217-231 (with M. Kilp) |
19. | On free, projective, and strongly flat acts Arch. Math., 47 (1986), 17-23 (with M. Kilp) |
18. | Unretractive Graphs (Graphs whose endomorphism monoid is a group) in: Theorie der Halbgruppen, Conference on Theory and Applications of Semigroups, Greifswald 1984, Mathematische Gesellschaft der DDR, Berlin DDR 1985, 68-76 |
17. | Centre and commutativity for wreath products of ordered semigroups Arch. Math., 44 (1985), 397-402 (with A. V. Mikhalev) |
16. | Wreath products of ordered semigroups Inverse ordered wreath products Semigroup Forum, 31 (1984), 181-191 (with A. Mikhalev) |
15. | Wreath products of ordered semigroups I. General properties, idempotent and regular Cartesian ordered isotone wreath products Semigroup Forum, 28 (1983), 331-350 (with A. Mikhalev) |
14. | Characterisation of monoids by properties of finitely generated right acts and their right ideals Recent Developments in the Algebraic, Analytical and Topological Theory of Semigroups, K. H. Hofmann, H. Jürgensen, H. J. Weinert (eds.), Lecture Notes in Mathematics 998, Springer, Berlin et al. 1983, 310-332 |
13. | Acts over Monoids. A Bibliographical Survey of Publications 1975-1981 BIS, Oldenburg 1982 (with M. Kilp, A. V. Mikhalev, L. A. Skornjakov) |
12. | Characterisation of monoids by torsion-free, flat, projective, and free acts Arch. Math., 36 (1981), 289-294 (with M. Petrich) |
11. | On the development of the algebraic theory of semigroups Simon Stevin, 54 (1980), 165-177 |
10. | Endomorphism monoids of free acts and 0-wreath products of monoids III. Standard involution and continuous endomorphisms Semigroup Forum, 19 (1980), 355-369 (with A. V. Mikhalev) |
9. | Endomorphism monoids of free acts and 0-wreath products of monoids II. Regularity Semigroup Forum, 19 (1980), 189-198 (with A. V. Mikhalev) |
8. | Endomorphism monoids of free acts and 0-wreath products of monoids I. Annihilator properties Semigroup Forum, 19 (1980), 177-187 (with A. V. Mikhalev) |
7. | Endomorphism monoids of free polygons Vestn. Mosk. Univ., Ser. Matem., Mech., 6 (1978), 81 (Russian) |
6. | A grade on Baer monoids Semigroup Forum, 13 (1976), 143-148 |
5. | Column monomial matrix monoids Math. Nachr., 74 (1976), 135-141 |
4. | Endomorphism monoids of acts over monoids Semigroup Forum, 6 (1973), 50-58 (with A. V. Mikhalev) |
3. | Morita equivalence of semigroups Uspechi Matem. Nauk, XXVII (1972), 173-174 (Russian) |
2. | Projectivity of acts and Morita equivalence of monoids, Semigroup Forum, 3 (1972), 359-370 |
1. | Special morphisms and amalgams in the category of commutative semigroups X. All-Union Conference on Algebra, vol. II, 117, Novosibirsk 1969 (Russian) |
Articles in journals and anthologies
B.) Modelling and professional practice
31. | Traffic analysis Hamburg Hbf Effective relief through TransRegio lines A new class in regional transport Fast, inexpensive and sustainable (with Jens Ode, Dieter Doege, in collaboration with Klaus Tüpker) 35 pages Prellbock Altona e. v. Issue 12 August 2021 |
30. | Back to punctuality. Delay analysis of the Cottbus - Wismar regional express, der Fahrgast 2/2014, 18 - 19 |
29. | Modelling in the education of mathematicians (and computer scientists?): in G. Engels, A. Oberweis, A. Zündorf (eds.): Modellierung 2001, 133-137 Lecture Notes in Informatics GI-Edition, Bonn 2001 |
28. | Ökosteuer - Soziale Kosten von Benzin, 24 pages, Oldenburg 2000 (authors' collective) |
27. | Development of suburban railway systems in medium-sized cities in: G. Frank, U.Meyerholt, E.Stein (eds.), Verkehrsinitiativen zum Umweltschutz, 315-328, Oldenburg 1999 |
26. | S-Bahn for Oldenburg? A mathematical-spatial planning model 78 pages, Oldenburg 1996 (author collective with P. Singer) |
25. | Patient support service in the central hospital Bremen-Ost An empirical organisational analysis 43 pages, 65 pages appendix, Oldenburg 1995 |
24. | Modelling in the clinical nursing service (Bremen East Hospital) 37 pages, Oldenburg 1994 (author collective with S. Grubitzsch) |
23. | Transport - a care problem a+l/Technik, No. 10 (1993) 10-16 (with J. Richter) |
22. | ÖPNV im Landkreis Vechta Verkehrsgutachten unter besonderer Berücksichtigung der Betriebs- und gesamt-wirtschaftlichen Kosten, der Bevölkerungsstruktur, der Pendlerbeziehungen und der Bedarfsentwicklung. 147 Seiten, Oldenburg 1991 P.p. des Landkreises Vechta (with H.E. Groß and J. Richter) |
21. | A networked and synchronised transport system Weser Ems 67 pages, Oldenburg 1991 (collective of authors with W. Ebenhöh) |
20. | A mathematical pig fattening model 82 pages, Oldenburg 1990 (authors' collective) |
19. | Modelling of a public transport network, 49 pages, Oldenburg 1989 (authors' collective) |
18. | Mathematicians in the economy in: I. Maass, W. Schlögelmann (eds.), Mathematik als Technologie? 94-109, Deutscher Studien Verlag, Weinheim 1989 (with H.E. Gross) |
17. | Mathematische Modellierung - Prinzipien und Qualifikationen in: A.M. Kempf, F. Wille (eds.), Mathematische Modellierung - ein Arbeitsbuch für Seminare, McGraw-Hll, 1986, 282-292 |
16. | Macroeconomic analysis of combined transport using the example of an efficiency analysis of the Rolling Road system, 75 pages, IVE Hannover 1988 |
15. | Road freight transport or rolling road - A resource balance model, Oldenburg 1985, also: Einblicke 5 (1987), 31-33 |
14. | University Education as Preparation for Professional Practice in: H.Neunzert (Ed.), Mathematics in Industry, Teubner Stuttgart 1984, 115-136 (with H.E. Gross) |
13. | Mathematical Modelling in University Education. An Experiment at the University of Oldenburg, Int. J. Math. Educ. Sci. Technol., 13 (1982), 779-787 (with H.E. Gross) |
12. | The single-phase teacher training programme as a field of experience for university teachers. in: W. Fichten, D. Spindler, U. Steinbrink (eds.) Dokumentation zur einphasigen Lehrerausbildung, vol. 5. Wissenschaft und Unterricht, 41-53, University of Oldenburg, Centre for Pedagogical Professional Practice, Oldenburg 1982 (with I. Pieper-Seier) |
11. | Philosophical aspects of mathematical modelling, M. z. Berufspraxis Math., Bielefeld 1980, H. 25, 99-108 |
10. | Philosophical aspects of mathematical modelling in: X.J.R. Avula, R. Bellmann, Y.L. Luke, A.K. Rigler (Eds.), Proceedings of the second International Conference on Mathematical Modelling, St. Louis, Missouri 1979, Rolla Missouri 1980, 739-744 |
9. | Some aspects of the relation between mathematics and reality in: B. Booss, M. Niss (Eds.): Mathematics and the real world, Birkhäuser, Basel, Boston, Stuttgart 1979, 82-86 (with J. Buurman) |
8. | The Impact of the Employment Situation of Mathematicians on University Education in: The role of mathematics in Industry, Proc. Third South East Asian Mathematical Symposium Kuala Lumpur 1978, Kuala Lumpur n.d., 46-53 (with H.E. Gross) |
7. | Studying mathematics, orientated towards academic appointments Uni-Berufswahlmagazin, 3 (1977), 25-27 |
6. | Mathematisation - Mathematics as a method M. z. Berufspraxis Math., Bielefeld 1977, H. 21, 113-127 |
5. | Questionnaire for mathematical scientists in: B. Booss, K. Krickeberg (eds.): Mathematisierung der Einzelwissenschaften, Birkhäuser, Basel 1976, 282-287 (with B. Booss) |
4. | Introduction to Mathematics M. z. Berufspraxis Math., Bielefeld 1975, . 15, 109-118 |
3. | Studieneinführung Mathematik Aspekte, Zeitschrift der Berufsberatung (1975) 6, 8-11 |
2. | Three problems from the professional practice of mathematicians in business M. z. Berufspraxis Math. Bielefeld 1974, H. 11, 61-78 |
1. | Project studies in mathematics M. z. Berufspraxis Math., Bielefeld 1973, H. 10, 1-45 (with D. Hinrichsen, H. Zessin) |
Further publications from the Algebraic Graph Theory group
12. | J. Kötters, Almost all graphs are rigid - revisited in: Discrete Math. 309 (2009) 5420 - 5424 |
11. | R. Kaschek, On unretractive graphs in: Discrete Math. 309 (2009) 5370 - 5380 |
10. | R. Kaschek, More on unretractive graphs in: V. Laan, S. Bulman-Fleming, R. Kaschek (Eds.), Semigroups, Acts and Categories with Applications to Graphs, Proceedings, Tartu 2007, Estonian Mathematical Society, Tartu 2008, 57 - 66 |
9. | Apirat Wanichsombat, Endo-completely-regular split graphs in: V. Laan, S. Bulman-Fleming, R. Kaschek (Eds.), Semigroups, Acts and Categories with Applications to Graphs, Proceedings, Tartu 2007, Estonian Mathematical Society, Tartu 2008, 138 - 142 |
8. | Somnuek Worawiset, On endomorphisms of Clifford semigroups. in: V. Laan, S. Bulman-Fleming, R. Kaschek (Eds.), Semigroups, Acts and Categories with Applications to Graphs, Proceedings, Tartu 2007, Estonian Mathematical Society, Tartu 2008, 143 - 150 |
7. | Xia Zhang, Clifford semigroups with genus zero in: V. Laan, S. Bulman-Fleming, R. Kaschek (Eds.), Semigroups, Acts and Categories with Applications to Graphs, Proceedings, Tartu 2007, Estonian Mathematical Society, Tartu 2008, 151 - 160 |
6. | Zhang X., Chen Y. Q., Wang Y.M., Chain conditions on essential subacts Northeast. Math. J., 2006, 22 (3): 357-368. |
5. | On homological classification of pomonoids by regular weak injectivity properties S-posets Xia Zhang, Valdis Laan, Central European Journal of Mathematics, 5(1), (2007), 181-200 |
4. | On unretractive graphs Roland Kaschek, ENDM 23 (2005) 41-50 |
3. | Almost all graphs are rigid - Revisited Jens Kötters, ENDM 23 (2005) 33-39 |
2. | Links between Latin squares, nets, graphs and groups: Work inspired by a paper of A. Barlotti and K. Strambach Aiso Heinze and Mikhail Klin, ENDM 23 (2005) 13-21 |
1. | Graphs with regular endomorphism monoid, E. Wilkeit, Arch. Math. 66 (1996), 344-352 |