\input zb-basic \input zb-ioport \iteman{io-port 04043227} \itemau{Smyth, M.B.} \itemti{Finite approximation of spaces.} \itemso{Category theory and computer programming, Workshop, Guildford/U.K. 1985, Lect. Notes Comput. Sci. 240, 225-241 (1986).} \itemab [For the entire collection see Zbl 0607.00015.] The aim of the paper is to prove that the domain theory technique of approximation via projections can be generalized so that it can be applied to locally compact spaces. The paper presents locally compact spaces via approximation by finite spaces and it suggests a similar approach to constructive spaces by extending traditional methods of domain theory to a suitable wider context and by establishing the finitary constructs by means of classical topological notions. \itemrv{G.Ciobanu} \itemcc{} \itemut{complete partial orders; Plotkin's SFP; ordered topological spaces; constructivism; domain theory; approximation via projections; locally compact spaces} \itemli{} \end