% unary encoding of natural numbers by +, 1, and 0
% with a definition of s
% needs case analysis to terminate

predicates([]).
precedence( [s,0,+,1] ).


X+0 = X.
X+s(Y) = s(X+Y).
1+X = s(X).
X+Y=Y+X.
X+(Y+Z)=(X+Y)+Z.

%X+Y=X+Z -> Y=Z.



:-sarp([1-9,12,13]).
%:-sarp(all).