Prolog and Logical definitions of plus/subtract

Hello,

I know that the logical definition of and plus and subtract in Prolog
is:
plus(0,N,N).
plus(s(M),N,s(Z)) :- plus(M,N,Z).

where s(X) is the successor of number X.

However, what would you do if you wanted to represent negative numbers?


Thanks,
John

.

Relevant Pages

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