Remark about the Boolean parts in the postulate-systems of closure, derivative and projective algebras.
Bolesław Sobociński · Notre Dame Journal of Formal Logic · 1973
BOLESLAW SOBOCINSKI1.An acquaintance with [7] is presupposed.Especially, in order to understand the proofs given in sections 2, 3 and 4 below a certain familiarity with the systems 9tt andftf, cf.[7], pp.531-539, is required.