A quick lesson on: What is IMP?

[Dimster]

Thanks for addressing this one Steve

So I gather, the string variables MUST equate to either a -1 or 0 ??? Somewhere in the conditions which set up the IMP, the variables being used in the Implied comparison need to equate to either a -1 or 0. 

A statement like A = 10 : B = 10 : A imp B, doesn't work??