*Definition 1 [#vb69ce9a] A topological space X is α-realcompact (or closed-complete) iff each 2-valued regular Borel measure in X is [[τ-additive]]. *Definition 2 [#ka504133] Same as [[a-realcompact]]. *Reference [#xe1f5f5d] :Definition 1| R.J.Gardner and W.F.Pfeffer, ''Borel Measures'', in "Handbook of Set-Theoretic Topology", Elsevier, 1984, 961-1043. :Definition 2| Nancy Dykes, Generalizations of Realcompact Spaces, Pacific Journal of Mathematics Vol. 33, No. 3, 1970.