# Dr Soren Riis

Email: s.riis@qmul.ac.uk
Telephone: +44 20 7882 6284
Room Number: Peter Landin, CS 420
Website: http://www.eecs.qmul.ac.uk/~smriis
Office Hours: Thursday 11:30-13:30, Wednesday 13:00-15:00

## Teaching

### Computability, Complexity and Algorithms (Undergraduate)

A theoretical course, which concerned with the theoretical core of Computer Science. The course covers some of the most successful algorithms as well as some of the most central decision problems. A large part of the course will focus on the NP versus P problem as well as other famous unsolved problem in Computer Science. To understand this problem we consider the issue of how one programming problem can be disguised as another apparently very different problem. This idea is very important in designing algorithms and plays a crucial role in the theory of NP-completeness.

### Logic and Discrete Structures (Undergraduate)

The module consists of two parts, each of fundamental importance for any serious approach to Computer Science: Logic and Discrete Structures. Logic has been called the Calculus of Computer Science. It plays a very important role in computer architecture (logic gates), software engineering (specification and verification), programming languages (semantics, logic programming), databases (relational algebra and SQL the standard computer language for accessing and manipulating databases), artificial intelligence (automatic theorem proving), algorithms (complexity and expressiveness), and theory of computation (general notions of computability). Computer scientists use Discrete Mathematics to think about their subject and to communicate their ideas independently of particular computers and programs. They expect other computer scientists to be fluent in the language and methods of Discrete Mathematics. In the module we consider Propositional logic as well as Predicate Calculus. We will treat Propositional Logic and Predicate Calculus as formal systems. You will learn how to produce and annotate formal proofs. As application we will briefly consider the programming language Prolog. This module will also cover a variety of standard representations, operations, properties, constructions and applications associated with selected structures from Discrete Mathematics (sets, relations, functions, directed graphs, orders).

## Research

### Research Interests:

Mathematical Logic, Complexity Theory, Proof Complexity, Algebraic Proof Complexity, Information Theory, Network Coding, Combinatorics and Reinforced Learning.

## Publications

• RIIS S, Gadouleau M (2019). Max-Flow Min-Cut Theorems on Dispersion and Entropy Measures for Communication Networks. nameOfConference

• Baber R, Christofides D, Dang NA et al. (2016). Graph Guessing Games and Non-Shannon Information Inequalities.. nameOfConference

• Cameron PJ, Dang AN, Riis S (2016). Guessing games on triangle-free graphs. nameOfConference

• Riis S, Martin U, Woodhouse N (2015). Ada Lovelace, a scientist in the archives. nameOfConference

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• Gadouleau M, Richard A, Riis S (2015). FIXED POINTS OF BOOLEAN NETWORKS, GUESSING GRAPHS, AND CODING THEORY. nameOfConference

• Gadouleau M, Riis S (2015). Memoryless computation: New results, constructions, and extensions. nameOfConference

• Riis S (2014). What makes a chess program original? Revisiting the Rybka case. nameOfConference

• RIIS SM, Barber, R, Christofides, D et al. (2013). Multiple unicasts, graph guessing games, and non-Shannon inequalities. 2013 International Symposium on Network Coding (NetCod)

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• Williams H, McOwan P, Riis S (2012). Making magic: applying artificial intelligence methods to design a psychophysically compelling illusion. nameOfConference

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• Riis S, Gadouleau M (2011). A dispersion theorem for communication networks based on term sets. nameOfConference

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• RIIS SM, Gadouleau M (2011). Graph theoretical constructions for Graph Entropy and Network Coding Based Communications. nameOfConference

• Cameron PJ, Gadouleau M, Riis S (2011). Combinatorial representations. nameOfConference

• RIIS SM, Gadouleau M (2011). Network Coding Theorem for Dynamic Communication Networks. Network Coding (NetCod), 2011 International Symposium

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• Gadouleau M, Riis S (2011). Computing without memory. nameOfConference

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• Gadouleau M, Riis S, IEEE (2011). Max-Flow Min-Cut Theorem for Renyi Entropy in Communication Networks. nameOfConference

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• Gadouleau M, Riis S (2010). Graph-theoretical Constructions for Graph Entropy and Network Coding Based Communications. nameOfConference

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• Gadouleau M, Riis S (2010). Max-Flow Min-Cut Theorems for Communication Networks Based on Equational Logic. nameOfConference

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• Wu T, Cameron P, Riis S (2009). On the guessing number of shift graphs. nameOfConference

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• RIIS SM (2009). On the asymptotic Nullstellensatz and Polynomial Calculus proof complexity. nameOfConference

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• Riis S (2008). On the asymptotic Nullstellensatz and Polynomial calculus proof complexity. nameOfConference

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• RIIS SM (2007). "Graph Entropy, Network Coding and Guessing games". nameOfConference

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• Riis S (2007). Reversible and irreversible information networks. nameOfConference

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• Riis S (2007). Information flows, graphs and their guessing numbers. nameOfConference

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• Riis S (2006). Information flows, graphs and their guessing numbers. nameOfConference

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• Riis S, Ahlswede R (2006). Problems in network coding and error correcting codes appended by a draft version of S Riis "utilising public information in network coding". nameOfConference

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• RIIS SM (2004). Linear versus non-linear Boolean functions in Network Flow. 38th Annual Conference on Information Sciences and Systems (CISS)

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• Dantchev SS, Riis S (2003). On Relativisation and Complexity Gap.. nameOfConference

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• Dantchev S, Riis S (2003). On relativisation and complexity gap for resolution-based proof systems. nameOfConference

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• Riis S, Sitharam M (2001). Uniformly generated submodules of permutation modules - Over fields of characteristic 0. nameOfConference

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• Hägele K, Ó Dúnlaing C, Riis S (2001). The complexity of scheduling TV commercials. nameOfConference

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• Dantchev S, Riis S (2001). "Planar" tautologies hard for Resolution. nameOfConference

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• Riis S (2001). A complexity gap for tree resolution. nameOfConference

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• Jensen KJ, Riis S (2000). Self-organizing letter code-book for text-to-phoneme neural network model. nameOfConference

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• Dantchev S, Riis S (2000). Tree resolution proofs of the weak Pigeon-Hole Principle. nameOfConference

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• Riis S (1997). Count(q) does not imply Count(p). nameOfConference

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• Riis S (1997). Bootstrapping the primitive recursive functions by only 27 colors. nameOfConference

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• Riis S (1997). Count(q) versus the pigeon-hole principle. nameOfConference

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• Andersson A, Miltersen PB, Riis S et al. (1996). Static dictionaries on AC0 RAMs: Query time Θ(√log n/log log n) is necessary and sufficient. nameOfConference

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