2020 applicants
People

Dr David Richerby

Lecturer
School of Computer Science and Electronic Engineering (CSEE)
Dr David Richerby
  • Email

  • Telephone

    +44 (0) 1206 874414

  • Location

    5A.536, Colchester Campus

  • Academic support hours

    Wednesday 1100-1200 Thursday 1300-1400

Profile

Qualifications

  • PhD University of Cambridge, (2003)

Appointments

University of Essex

  • Lecturer, Computer Science and Electrical Engineering, University of Essex (1/10/2019 - present)

Research and professional activities

Research interests

Algorithms

Design and analysis of algorithms, typically to solve discrete combinatorial problems. I'm particularly interested in counting problems, where we wish to know how many solutions exist (e.g., how many different values for the variables make a given Boolean formula true). Many of these problems are computationally intractable, so approximation algorithms play an important role.

Open to supervise

Computational complexity theory

Classification of problems according to their level of computational difficulty. I'm particularly interested in dichotomy theorems, which show that, depending on a certain parameter, a problem will either be relatively easy or extremely hard, with no middle ground.

Open to supervise

Constraint satisfaction problems

Constraint satisfaction problems ask if it is possible to assign values to given variables, while satisfying given constraints – for example, to assign rooms and times to lectures without having two classes in the same room at the same time or requiring students to attend two classes at the same time. I'm also interested in variants, such as graph homomorphisms and M-partitions of graphs.

Open to supervise

Stochastic processes

Particularly the Moran process, which models the random spread of genetic mutations through geographically structured populations.

Open to supervise

Teaching and supervision

Current teaching responsibilities

  • Object-Oriented Programming (CE152)

  • Data Structures and Algorithms (CE204)

Publications

Journal articles (10)

Goldberg, L., Lapinskas, J. and Richerby, D., (2020). Phase transitions of the Moran process and algorithmic consequences. Random Structures and Algorithms. 56 (3), 597-647

Galanis, A., Göbel, A., Goldberg, LA., Lapinskas, J. and Richerby, D., (2017). Amplifiers for the Moran Process. Journal of the ACM. 64 (1), 1-90

Bulatov, A., Goldberg, LA., Jerrum, M., Richerby, D. and Živný, S., (2017). Functional clones and expressibility of partition functions. Theoretical Computer Science. 687, 11-39

Dyer, M., Goldberg, LA. and Richerby, D., (2016). Counting 4x4 matrix partitions of graphs. Discrete Applied Mathematics. 213, 76-92

Díaz, J., Goldberg, LA., Richerby, D. and Serna, M., (2016). Absorption time of the Moran process. Random Structures & Algorithms. 49 (1), 137-159

Göbel, A., Goldberg, LA. and Richerby, D., (2016). Counting Homomorphisms to Square-Free Graphs, Modulo 2. ACM Transactions on Computation Theory. 8 (3), 1-29

Chen, X., Dyer, M., Goldberg, LA., Jerrum, M., Lu, P., McQuillan, C. and Richerby, D., (2015). The complexity of approximating conservative counting CSPs. Journal of Computer and System Sciences. 81 (1), 311-329

Göbel, A., Goldberg, LA., McQuillan, C., Richerby, D. and Yamakami, T., (2015). Counting List Matrix Partitions of Graphs. SIAM Journal on Computing. 44 (4), 1089-1118

Díaz, J., Goldberg, LA., Mertzios, GB., Richerby, D., Serna, M. and Spirakis, PG., (2014). Approximating Fixation Probabilities in the Generalized Moran Process. Algorithmica. 69 (1), 78-91

Göbel, A., Goldberg, LA. and Richerby, D., (2014). The complexity of counting homomorphisms to cactus graphs modulo 2. ACM Transactions on Computation Theory. 6 (4), 1-29

Conferences (6)

Galanis, A., Göbel, A., Goldberg, LA., Lapinskas, J. and Richerby, D., (2016). Amplifiers for the Moran process

Göbel, A., Goldberg, LA. and Richerby, D., (2015). Counting homomorphisms to square-free graphs, modulo 2

Díaz, J., Goldberg, LA., Richerby, D. and Serna, M., (2014). Absorption time of the Moran process

Gobel, A., Goldberg, LA., McQuillan, C., Richerby, D. and Yamakami, T., (2014). Counting List Matrix Partitions of Graphs

Göbel, A., Goldberg, LA. and Richerby, D., (2014). Counting homomorphisms to cactus graphs modulo 2

Dyer, ME. and Richerby, DM., (2010). On the complexity of #CSP

Contact

david.richerby@essex.ac.uk
+44 (0) 1206 874414

Location:

5A.536, Colchester Campus

Academic support hours:

Wednesday 1100-1200 Thursday 1300-1400