Investigations in protothetic.
Audoënus Le Blanc · Notre Dame Journal of Formal Logic · 1985
In this article I present some results of five years' research into Lesniewski's protothetic.ι I outline deductions from the axiom A n considerably shorter than those previously known (see [9]) and I derive the laws of implication from this axiom without using the rule of extensionality. 2Since this paper can best be read in the light of articles by Professor Sobociήski published in this Journal (see [8], [9], and [10]), I have largely adopted his conventions of symbolism, and the following symbols in particular: a The rule permitting definitions of new constants (see [8], pp.58-59).β The rule for distributing quantifiers (see [8], p. 59).0 An informal abbreviation for ' [u] .