On The Range Of Boolean Transformation
A theorem is proved which could be considered as a bridge between the combinatorics which have a beginning in the dyadic spaces theory and the partition calculus.
We investigate, in set theory without the Axiom of Choice , the set-theoretic strength of the statement Q(n): For every infinite set X, the Tychonoff product , where 2 = 0,1 has the discrete topology, is n-compact, where n = 2,3,4,5 (definitions are given in Section 1). We establish the following results: (1) For n = 3,4,5, Q(n) is, in (Zermelo-Fraenkel set theory minus ), equivalent to the Boolean Prime Ideal Theorem , whereas (2) Q(2) is strictly weaker than in set theory (Zermelo-Fraenkel set...
We investigate the question whether a system of homogeneous linear equations over is non-trivially solvable in provided that each subsystem with is non-trivially solvable in where is a fixed cardinal number such that . Among other results, we establish the following. (a) The answer is ‘No’ in the finite case (i.e., being finite). (b) The answer is ‘No’ in the denumerable case (i.e., and a natural number). (c) The answer in case that is uncountable and is ‘No relatively consistent...