%0 Report
%D 2002
%T XCB, the Last of the Shortest Single Axioms for the Classical Equivalential Calculus
%A L. Wos
%A D. Ulrich
%A B. Fitelson
%X It has long been an open question whether the formula XCB = EpEEEpqErqr is, with the rules of substitution and detachment, a single axiom for the classical equivalential calculus. This paper answers that question affirmatively, thus completing a search for all such eleven-symbol single axioms that began seventy years ago.
%B Bull. Section Logic
%P 120-134
%8 06/2002
%G eng
%1 http://www.mcs.anl.gov/papers/P966.pdf