Re: arithmetic functions? (rank beginner)

On Mon, 19 Dec 2005 06:41:33 +0100, Paul Shannon <pshannon@xxxxxxxxxxxxxxxxxx> 
wrote:

> This must be a very dumb question, but I am stuck.
>
> I have built pl from source on both Mac os x 1.4, and  on linux.
> In neither case do arithmetic functions seem to be available.
>
>   ?- 2 + 2.
>    ERROR: Undefined procedure: (+)/2
>
> What obvious fact am I missing?
Try:

?- X is 2+2.

X = 4