Re: logical expressions

*To*: mathgroup at yoda.ncsa.uiuc.edu*Subject*: Re: logical expressions*From*: Jim_Wendel at ub.cc.umich.edu*Date*: Tue, 13 Nov 90 09:25:34 EST

This is about Paul Abbott's note of 10/28, logical expressions. The second example, supposedly of an invalid formula, is incorrect, in the sense that the formula evaluates to q for every p, not to false; this is readily checked by doing a truth-table by hand. Furthermore, what is the role of the quantity e=Rep[1,gbool,2}? It evaluates to 1, so why not just use 1, or nothing at all in multiplicative environments, e.g. and[x_,y_]:=x y, rather than e x y?