Semi-group compactifications of Algebraic Groups

We show that for algebraic groups over local fields of characteristic zero, the following are equivalent: Every homomorphism has a closed image, every unitary representation decomposes into a direct sum of finite-dimensional and mixing representations, and that the matrix coefficients are dense within the algebra of weakly almost periodic functions over the group. In our proof, we employ methods from semi-group theory. We establish that algebraic groups are compactification-centric, meaning sG = Gs for any element s in the weakly almost periodic compactification of the group G.