**October 18**

**Brian Wynne**,
CUNY

**Old and new decidability results for theories of Abelian lattice-ordered groups**

An Abelian lattice-ordered group (l-group) is an Abelian group with a lattice order that is invariant under translations. Examples include $C(X)$, the set of continuous real-valued functions on a topological space $X$ with pointwise operations and order, the $L_p$ spaces, and certain spaces of measures. After surveying some of the known decidability results for various classes of l-groups, I will present new decidability results concerning existentially closed l-groups.