  Contact algebra is one of the main tools in region-based theory of space. In
\cite{dmvw1, dmvw2,iv,i1} it is generalized by dropping the operation Boolean
complement. Furthermore we can generalize contact algebra by dropping also the
operation meet. Thus we obtain structures, called contact join-semilattices
(CJS) and structures, called distributive contact join-semilattices (DCJS). We
obtain a set-theoretical representation theorem for CJS and a relational
representation theorem for DCJS. As corollaries we get also topological
representation theorems. We prove that the universal theory of CJS and of DCJS
is the same and is decidable.
