Анотація:
Spaces of selfadjoint elements of a C*-algebra or a von Neumann algebra, and also JB- and JBW-algebras are examples of order-unit spaces. A von Neumann algebra and a JBW-algebra possess predual spaces, but, generally speaking, a JB-algebra and a C*-algebra don't have this property. In this work, conditions are found for an order-unit space to possess a predual space. Moreover, a condition is obtained characterizing JBW-algebras among order-unit spaces having a predual space.