Prof. Abdullahi Umar

Department of Mathematics, College of Arts and Sciences

Khalifa University of Science and Technology, United Arab Emirates

Email: abdullahi.umar@ku.ac.ae

Qualifications

1992 Ph.D., University of St Andrews, Scotland, U.K.

1987 M.Sc., Ahmadu Bello University (ABU), Zaria, Nigeria

1983 B.Sc., Ahmadu Bello University (ABU), Zaria, Nigeria

Publications (Selected)

1. Adeshola, A. D. and Umar, A., Combinatorial results for certain semigroups of order-preserving full contraction mappings of a finite chain, JCMCC, 106 (2018), 37-49.
2. Laradji, A. and Umar, A., Lattice paths and partial order-preserving transformations, Utilitas Mathematica, 101 (2016), 23-36. (S & M).
3. Umar, A., Some Combinatorial Problems in the Theory of Partial Transformation Semigroups. Algebra and Discrete Math., 17 (2014), 110-134.
4. Umar, A., Some combinatorial problems in the theory of symmetric inverse semigroup. Algebra and Discrete Math., 9 (2010), 115-126. (M).
5. Umar, A. A class of quasi-adequate transformation semigroups. Portugaliae Mathematica Vol. 51 Fasc. 4 (1994), 553-570.

Profile Details

Dr. Abdullahi Umar earned his PhD in Mathematics from the University of St Andrews, Scotland in 1992, following on his first class Hons BSc in Mathematics from Ahmadu Bello University, Zaria, Nigeria (1983). After holding several positions in universities in Nigeria, Dr. Umar joined the King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia in 1997 as an assistant professor. He was promoted to the rank of Associate Professor at KFUPM in 2005. In 2007, he moved to Sultan Qaboos University (SQU), Oman, where he remained until 2014 when he moved to the Petroleum Institute, (now part of Khalifa University of Science and Technology) as an associate professor and was promoted to the rank of full professor in 2020. While at SQU, he won a substantial research grant (approx. US$150,000) from The Research Council TRC of Oman for “Studies in semigroups of contractions mappings of a finite chain”. Dr. Umar is an expert on the theory of semigroups of transformations, especially on their algebraic, combinatorial and rank properties. He has published more than 50 peer reviewed research papers (690+ citations; h-index = 15 – Google Scholar). In 2015-16, a German mathematician and his coauthors, Billhardt et al. recognized the importance of his constructions (in his paper of 1994), by exhibiting certain universal properties it possesses and named E(F_A) and F_A as Umar band and Umar semigroup, respectively in his honor. It is one of the greatest achievements to see a mathematical object named after someone, more so during their lifetime. He also has interests in recreational mathematics: magic squares and cubes, and calendars. As a faculty member Dr. Umar has co-supervised six PhD students and three MSc students to graduation. He is a journal referee for several international journals and is reviewer for Mathematical Reviews (since 2008). He is also currently a member of the Nigerian Mathematical Society (NMS, since 1987), Edinburgh Mathematical Society (EMS, since 2008), American Mathematical Society (AMS, since 2016) and Combinatorial and Mathematical Society of Australasia (CMSA, since 2011, now a life member).