Boris, this is becoming better. It’s almost good. Thanks.
As you can see, some queries were not answered correctly by the program (I don’t know why). I’m content anyways.
I didn’t understand when and where should i type the three backticks.
pi@raspberrypi:~ $ swipl Warning: Package bddem: no binary for architecture armhf Welcome to SWI-Prolog (Multi-threaded, 32 bits, Version 7.2.3) Copyright (c) 1990-2015 University of Amsterdam, VU Amsterdam SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under certain conditions. Please visit http://www.swi-prolog.org for details. For help, use ?- help(Topic). or ?- apropos(Word). ?- [office]. true. ?- supervises(black,green). true . ?- supervises(gray,green). false. ?- adminWorker(black). true. ?- supervises(brown,white). false. ?- supervises(brown, white). false. ?- supervises(brown,black). true . ?- trace. true. [trace] ?- notrace. true. [debug] ?-