prolog function returning memory locations instead of values...

ERROR: Undefined procedure: (:-)/2...

How to use variables in Prolog query shell?...

Shell commands from the top-level...

Make Prolog return one solution and stop showing the query option...

Change the Return response of Prolog...

What does "?-" mean in Prolog?...

Understanding rules - false as answer...

Learn prolog exercise 2.3...