-
In approval-based committee elections, voters vote by submitting an approval ballot, which indicates which candidates the voter approves of, with the purpose of electing a fixed size committee. Recent impossibility results have shown that approval-based committee voting rules that select committe...
-
Goal-based voting is a new voting framework in which agents can submit propositional formulae as their goals. We study iterated applications of the majorities and approval rules in this framework. We introduce notions of satisfaction based on the Hamming distance between an agent’s goal and the i...
-
This thesis deals with the different meanings generated by the following two
sentences:
(1) a. You may have coffee or tea, but I don’t know which.
b. You may have coffee or tea, but I don’t care which.
Whereas the former seems to presuppose that only one alternative is possible (a...
-
This thesis presents an epistemic logic for modeling Zero-Knowledge proofs and other cryptographic protocols. We consider multi-agent interactions where a prover convinces a verifier of some proposition φ, with the verifier learning nothing more than the validity of φ. By enriching existing crypt...
-
The thesis presents an analysis of the hardness results for learning deterministic finite automata from signed data examples. Focusing on the conditions which allow for learning to take place, we investigate a notion of a “fair” sample that would typically permit learning. Despite demonstrating t...
-
The Condorcet Jury Theorem (CJT) is considered one of the cornerstones of the wisdom of the crowd, i.e. the idea that large groups of people are better at tracking the truth than small ones. However, such a result is often criticized on the ground that its assumptions are unrealistic. In this the...
-
We study relation lifting in the context of universal coalgebra. In particular, we develop a family of logics based on the cover modality.
Firstly, we prove a Hennessy-Milner-style theorem, showing that on finite-branching coalgebras, logical equivalence coincides with a particular form of bisim...
-
Traditional epistemic logics generally define knowledge as truth in all epistemic alternatives. This approach has two shortcomings: first, the link between knowledge and justification is not represented. Second, epistemic agents are highly idealised and suffer from the defect of logical omniscien...
-
This thesis investigates coalgebraic generalizations of two multiagent modal logics from the literature, in which truth values are identified with sets of agents. In the first logic, which is due to Melvin Fitting, the truth value of a formula is identified as the set of agents for whom the formu...
-
In this thesis, we study positive (non-distributive) logics and their modal extensions by means of duality theory. Our work is inspired by topological dualities for semilattices and lattices established by Jipsen and Moshier (2014). First we construct a choice-free version of this duality using m...
-
Cyclic derivations are finite graphs in which adjacent nodes are labeled by sequents according to locally sound derivation rules. These graphs serve as a finite representation of the infinite derivation trees obtained by unraveling them. To be considered proofs, such derivations need to satisfy a...