# Teh Wen Chean

ORCID ID: 0000-0001-8424-9820 MathSciNet Author ID: 1092420

Researcher ID: B-2632-2018 Scopus Author ID: 56385389300

Dr. Teh Wen Chean graduated from The Ohio-State University, under the mentorship of Timothy Carlson. His current research interests are in combinatorics, graph theory, discrete mathematics related to theoretical computer science, and discrete optimization. Since joining USM in early 2013, he has successfully published thirty one articles in various mainstream journals in the area of logic, combinatorics, and theoretical computer science. He is the principal investigator of a few grants, including the national FRGS grant twice. His publication in the Bulletin of the Malaysian Mathematical Sciences Society received the best article award by PERSAMA in 2015. His work on Parikh matrices especially is quite fruitful and results so far in fourteen publications in mostly ISI journals, some among which result from a collaborative effort with respectable Professor Emeritus Adrian Atanasiu from Romania, Professor Emeritus K.G. Subramanian from India, and his protege Ghajendran Poovanandran. Due to this success, he is currently active in another relatively new topic from a similar area, called reaction systems. Furthermore, he has successfully ventured into some topics in graph theory, particularly graph burning. For more information on his research contributions, please visit https://www.researchgate.net/profile/Wen_Chean_Teh

## Research

My research interests is in combinatorics, graph theory, discrete mathematics in relation to computer science, and combinatorial optimization. I have recently published in three different topics, namely, reaction systems, Parikh matrices, and Ramsey algebras. Furthemore, I have successfully secured some research grant for each topic. The research on reaction systems is gaining some momentum lately.

First International Workshop on Reaction Systems

Second International Workshop and School on Reaction Systems

I am interested in exploration of new research directions and open to collaboration with existing reseachers or potential students. I am currently venturing into the research on burning number of graphs and if you are on board, together this pioneering endeavour will reach a greater height.

## Financial Support

Monthly financial support (~RM1800 for PhD and ~RM1300 for MSc) are available from my research grant(s) to international and local students based on merit and on a competitive basis. The duration of support is at most 2.5 years for PhD and 1.5 years for MSc. The supported student is expected to work on problems related to the grant's topic. The student is expected to work closely with me and to graduate on time. Meanwhile, highly qualified students are recommended to apply for the USM or TWAS-USM fellowship.

Vacancies for postdoctorate research positions may also be available anytime, supported by USM or through the TWAS-USM postdoctoral fellowship. The window of application is short. If you are interested to collaborate with me through such opportunity, please send me your resume earlier and keep in touch.

MSc (Mixed Mode) and undergraduate students are welcome to work on some research-oriented projects. Potential undergraduate students can even start during their third year long semester break.

Reserch Grants (as principal investigator)

A New Approach Towards Solving the Burning Number Conjecture of Graph Burning, USM RU grant, 1 Jan 2020 - 31 Dec 2022.

Minimal Reaction Systems as Novel Canonical Bio-Inspired Computing Models, National FRGS grant, 1 Jan 2019 - 31 Dec 2020.

Parikh Rewriting System as a Feasible Solution to the Elusive Injectivity Problem of Parikh Matrices, USM RU grant, 1 Mar 2017 - 31 Aug 2019.

Ramsey Orderly Algebras - a Route to an Ultimate Characterization of Ramsey Algebras, National FRGS grant, 1 Dec 2014 - 31 May 2017.

On Parikh Matrices and the Injectivity Problem, USM short term grant, 15 Aug 2014 - 14 Feb 2017.

## Publications

Selected Publications

1 W. C. Teh, Ramsey Algebras and the Existence of Idempotent Ultrafilters, *Arch. Math. Log.* 55(3-4) (2016), 475-491.

2 W. C. Teh, Ramsey Algebras, *J. Math. Log.* 16(2) (2016), 1650005, 16 pp.

3 W. C. Teh, Parikh Matrices and Parikh Rewriting Systems, *Fund. Inform.* 146(3) (2016), 305-320.

4 W. C. Teh*, A. Atanasiu and G. Poovanandran, On Strongly M-Unambiguous Prints and Serbanuta’s Conjecture for Parikh Matrices, *Theoret. Comput. Sci.* 719 (2018), 86-93.

5 G. Poovanandran and W. C. Teh*, Elementary Matrix Equivalence and Core Transformation Graphs for Parikh Matrices, *Discrete Appl. Math. *251 (2018), 276-289.

6 W. C. Teh*, A. Atanasiu, Irreducible Reaction Systems and Reaction System Rank, *Theoret. Comput. Sci.* 666 (2017), 12-20.

7 W. C. Teh, Compositions of Functions and Permutations Specified by Minimal Reaction Systems, * Internat. J. Found. Comput. Sci.* 29(7) (2018), 1165-1179.

8 W. C. Teh*, Z. C. Ng, M. Javaid, and Z. J. Chern, Parikh Word Representability of Bipartite Permutation Graphs, *Discrete Appl. Math.* (to appear)

9 T. S. Tan, W.C. Teh*, Graph Burning: Tight Bounds on the Burning Numbers of Path Forests and Spiders (preprint)

All ISI/MathScinet Publications

*****Corresponding Author

1 W. C. Teh, Ramsey Algebras and Strongly Reductible Ultrafilters, *Bull. Malays.** Math. Sci. Soc.* (2) 37(4) (2014), 931-938.

2 W. C. Teh*, K. H. Kwa, Core Words and Parikh Matrices, *Theoret. Comput. Sci. *582 (2015) 60-69.

3 W. C. Teh, On Core Words and the Parikh Matrix Mapping, *Internat. J. Found.** Comput. Sci.* 26(1) (2015), 123-142.

4 Z. S. Tan*, M. H. Ang, W. C. Teh, Group Ring Codes over a Dihedral Group, *Malays. J. Math.** Sci.* 9(S) (2015), 37-52.

5 W. C. Teh, Ramsey Algebras and the Existence of Idempotent Ultrafilters, *Arch. Math. Log.* 55(3-4) (2016), 475-491.

6 W. C. Teh, Ramsey Algebras, *J. Math. Log.* 16(2) (2016), 1650005, 16 pp.

7 W. C. Teh*, A. Atanasiu, On a Conjecture about Parikh Matrices, *Theoret.Comput. Sci.* 628 (2016), 30-39.

8 W. C. Teh, Parikh Matrices and Parikh Rewriting Systems, *Fund. Inform.* 146(3) (2016), 305-320.

9 A. Atanasiu, W. C. Teh*, A New Operator over Parikh Languages, *Internat. J.** Found. Comput. Sci.* 27(6) (2016), 757-769.

10 W. C. Teh, Parikh Matrices and Strong M-equivalence, *Internat. J. Found. Comput.** Sci. *27(5) (2016), 545-556.

11 W. C. Teh, Separability of M-equivalent Words by Morphisms, *Internat. J. Found.* *Comput. Sci. *27(1) (2016), 39-52.

12 W. C. Teh*, A. Atanasiu, Irreducible Reaction Systems and Reaction System Rank, *Theoret. Comput. Sci.* 666 (2017), 12-20.

13 W. C. Teh, Ramsey Algebras and Formal Orderly Terms, *Notre Dame J. Form. Log. *58(1) (2017), 115-125.

14 W. C. Teh*, A. Atanasiu, Minimal Reaction Systems Revisited and Reaction System Rank, *Internat. J.** Found. Comput. Sci.* 28(3) (2017), 247-261.

15. A. Rajah, W. C. Teh* and Z. Y. Teoh, Role of Associativity in Ramsey Algebras, *Proc. Indian Acad. Sci. Math. Sci.* 127(5) (2017), 769-778.

16 W. C. Teh* and Z. Y. Teoh, Ramsey Orderly Algebras as a New Approach to Ramsey Algebras, *East-West J. Math. *19(1) (2017), 89-102.

17 G. Poovanandran, W. C. Teh*, On M-Equivalence and Strong M-Equivalence for Parikh Matrices, * Internat. J. Found. Comput. Sci.* 29(1) (2018), 123-137.

18 Z. Y. Teoh and W. C. Teh*, Heterogeneous Ramsey Algebras and Classification of Ramsey Vector Spaces, *Bull. Malays.** Math. Sci. Soc.* (2) 41(2) (2018), 1011-1028.

19 W. C. Teh*, N. Womasuthan, On Irreducible Reaction Systems, *Malays. J. Math. ** Sci.* 12(1) (2018), 25-34.

20 W. C. Teh*, A. Atanasiu and G. Poovanandran, On Strongly M-Unambiguous Prints and Serbanuta’s Conjecture for Parikh Matrices, *Theoret. Comput. Sci.* 719 (2018), 86-93.

21 W. C. Teh*, K. G. Subramanian, B. Somnath, Order of Weak M-Relation and Parikh Matrices, *Theoret. Comput. Sci. *743 (2018), 83-92.

22 W. C. Teh, Compositions of Functions and Permutations Specified by Minimal Reaction Systems, * Internat. J. Found. Comput. Sci.* 29(7) (2018), 1165-1179.

23 G. Poovanandran and W. C. Teh*, Elementary Matrix Equivalence and Core Transformation Graphs for Parikh Matrices, *Discrete Appl. Math. *251 (2018), 276-289.

24 M. Javaid*, M. Ahmad, M. Hussain and W. C. Teh, Bounds of *F*-Index for Unicyclic Graphs with Fixed Pendent Vertices, *J. Prime. Res. Math.** *14 (2018), 51-61.

25 M. Javaid*, M. Abbas, J. Liu, W. C. Teh and J. Cao, Topological Properties of Four-Layered Neural Networks, *J. Artificial Intelligence Soft Comput. Res.** *9(2) (2019), 111-122.

26 Z. Y. Teoh and W. C. Teh*, A Ramsey Algebraic Study of Matrices, * Algebra Discrete Math.* 27(1) (2019), 85-98.

27 G. Poovanandran and W. C. Teh*, Strong (2.t) and Strong (3.t) Transformations for Strong M-Equivalence, *Internat. J.** Found. Comput. Sci.*

**30(5) (2019), 719-733.**

28 A. Atanasiu, G. Poovanandran and W. C. Teh*, Parikh Matrices for Powers of Words, *Acta Inform** . *56(6) (2019), 521-535.

29 Z. J. Chern and W. C. Teh*, Extension of Parikh Matrices to Terms and Its Injectivity Problem, *Malays. J. Math.** Sci.* 13(S) April(2019), 147-156.

30 M. Javaid*, M. Raza, M. U. Rehman, W. C. Teh and J. Cao, Minimum Algebraic Connectivity of Graphs Whose Complements are Bicyclic with Two Cycles, *J. Discrete Math. Sci. Cryptogr. *(to appear)

31 A. Atanasiu, G. Poovanandran*, and W.C. Teh, Parikh Determinants, In: Mercaş R., Reidenbach D. (eds) Combinatorics on Words. WORDS 2019. *Lecture Notes in Comput. Sci.*, vol 11682. Springer, Cham

32 A. Atanasiu, G. Poovanandran, and W. C. Teh*, Parikh Motivated Study in Repetition in Words, *Bull. Math. Soc. Sci. Math. Roumanie *62(4) (2019), 325-340.

33 A. Raheem*, M. Javaid, W. C. Teh, S. Wand, and Jia-Bao Liu, M-Polynomial Method for Topological Indices of 2D-lattice of Three-layered Single-walled Titania Nanotubes, *J. Inf. Optim. Sci. *(to appear)

34 W. C. Teh, Parikh-friendly Permutations and Uniformly Parikh-friendly Words, * Australas. J. Combin. *76(1) (2020), 208-219.

35 W. C. Teh*, Z. C. Ng, M. Javaid, and Z. J. Chern, Parikh Word Representability of Bipartite Permutation Graphs, *Discrete Appl. Math.* (to appear)

36 G. Poovanandran and W. C. Teh*, M-Ambiguity Sequences for Parikh Matrices and Their Periodicity Revisited, *Bull. Malays.** Math. Sci. Soc. *(to appear)

The following manuscripts are under review.

1 T. S. Tan, W.C. Teh*, Graph Burning: Tight Bounds on the Burning Numbers of Path Forests and Spiders

2 Z. J. Chern, K.G. Subramanian, A. Ahmad, and W. C. Teh*, A New Study of Parikh Matrices Restricted to Terms

3 W. C. Teh, On M-Unambiguity of Parikh Matrices (supposed to appear in a special issue of AMC2016)

4 W. C. Teh, Simulation of Reaction Systems by the Minimal Ones

5 K. T. Nguyen, W. C. Teh, and H. K. Pho*, A Linear Time Algorithm for Connected *p*-Centdian Problem on Block Graphs

The following works are still under construction or ongoing.

1 Some problems on evolving reaction systems (on hold)

2 Some problems related to the word problem (final draft completed by 15 Jan 2020)

3 Continuation of the study on simulation of reaction systems (ongoing)

4 Continuation of the study on burning numbers (to be continued)

5 Some open problem related to palindromes (on hold)

6 Some new idea and problems for Parikh matrices (initiated)

Finally, I would be happy to collaborate with young researchers and PhD students in the topic of their interests.

## Teaching

“There is no such thing as an unmotivated student. There are, however, students in unmotivated states” — Eric Jensen.

Ever since joining USM in early 2013, it is my pleasure to be assigned to teach various pure mathematics courses, both at the undergranduate and the graduate level, which put more emphasis on abstraction and rigor relatively among the courses offered. Among all courses, I enjoy teaching Calculus I to the undergraduate freshmen the most. Guided by Eric Jensen’s quote, I consider my role as a Calculus instructor not so much as a foundational knowledge disseminator that equips the students for the rest of the mathematics courses, but as a motivator that galvanizes each individual student to be more independent and to live up to his/her potential so that he/she is more prepared for the challenges ahead in his future. Appreciation goes to the dedicated teachers from the Math Cafe that provides gratis tutoring to the freshmen.

MAT100 Mathematical Foundations (2016/2017 Sem 1, 2017/2018 Sem 1, 2019/2020 Sem 1)

MAT101 Calculus I (2013/2014 Sem 1, 2014/2015 Sem 2, 2015/2016 Sem 2, 2016/2017 Sem 2, 2017/2018 Sem 2)

MAT201 Calculus II (2018/2019 Sem 1)

MSS301 Real Analysis (2014/2015 Sem 1)

MGM501 Analysis (2012/2013 Sem 2)

MGM531 Euclidean Geometry (2013/2014 Sem 2)

## Graduate Supervision

As a mentor to my research mode students, I always share my professional experience and knowledge, nurturing them into all-around academicians in the future. I will provide them with necessary assistance at the right moment so that they can live up to their own potential. Within slightly over two years, my former student Dr. Ghajendran Poovanandran has completed seven manuscripts for consideration by ISI journals, six of which have been accepted for publication. He also received the best student presentation award in the 4th International Conference on Mathematical Sciences (ICMS4). He has successfully joined Asia Pacific University of Technology & Innovation as a faculty member, before passing his Viva with flying colors.

Ghajendran Poovanandran, Ph.D., main supervisor, completed in 2019, on Parikh matrices.

Zu Yao Teoh, Ph. D., main supervisor, completed in 2018, on Ramsey algebras.

Zi Shyuan Tan, M.Sc., co-supervisor, completed in 2016, on group ring codes.

Zi Jing Chern, M.Sc. (mixed mode), main supervisor, completed in 2019, on Parikh matrices.

Ghajendran Poovanandran, M.Sc. (mixed mode), main supervisor, completed in 2016, on Parikh matrices.

Nhivashni Womasuthan, M.Sc. (mixed mode), main supervisor, completed in January 2017, on reaction systems.

## Recognition

Phil Huneke Excellence in Teaching Award, Ohio-State University, 2008.

Main Award of PERSAMA (category of publication), 2015.

Honorable Mention Award of PERSAMA (category of publication), 2019.

I am a frequent reviewer for the AMS Mathematical Reviews. I was also an invited reviewer for the following ISI journals.

Advanced Applied Mathematics (Elsevier)

Discrete Applied Mathematics (Elsevier, twice)

Information and Computation (Elsevier)

International Journal of Foundations of Computer Science (World Scientific)

Acta Informatica (Springer)

Fundamenta Informaticae (IOS Press)

Punjab University Journal of Mathematics

I was the thesis examiner for the following students.

Lois Adewoye Ademola (PhD, 2017) - Associativity of Moufang Loops of Odd Order

Ng Zhen Chuan (PhD, 2017) - Bohr's Inequality and its Extensions

## Major Presentations

Graph Burning: Tight Bounds on the Burning Numbers of Path Forests and Spiders, Joint Mathematics Seminar USM-ITB, Bandung, 23 Jan 2020.

Parikh Rewriting Systems - A New Approach to the Injectivity Problem of Parikh Matrices, International Congress of Mathematicians, Rio de Janeiro, 1-9 Aug 2018.

A Note on Simulation of Reaction Systems by the Minimal Ones, International Conference on Mathematical Sciences and Statistics, Putrajaya, 6-8 Feb 2018.

Introduction of Ramsey Orderly Algebras as Localized Versions of Ramsey Algebras, International Conference of Mathematics and Applications, Bangkok, 17-19 Dec 2016.

Rank of Functions Specified by Reaction Systems, Mahidol-USM Joint-Workshop, Mahidol University, 16 Dec 2016.

On M-unambiguity of Parikh Matrices, Asian Mathematical Conference, Bali, 25-29 Jul 2016.

Ramsey Algebras, International Congress of Mathematicians, Seoul, 13-21 Aug 2014.

## Membership

Malaysian Mathematical Sciences Society

American Mathematical Society

European Mathematical Society

European Association for Theoretical Computer Science

Association for Symbolic Logic

The Ohio-State University Alumni Association

Universiti Sains Malaysia Alumni Association

p/s: Memberships are intermittent.