This week, Honours student Caity McGregor will be giving the SUMS talk. Pizza and drinks will be available afterwards, as always! Abstract: Having studied maths at uni, most of us are familiar with First Order Logic without having considered the formalisation of it. Stepping back to Propositional Logic and then extending to Modal Logic, we will explore some beautiful maths that models necessity and possibility, and hear about some of the core results of this non-classical logic.