Output of propositional functions

[Alberto Candel]

A propositional function outputs 0/1 or True/False depending on ...? Maybe someone knows how to always get True/False. I explain:

The function gt0(x):=x>0 outputs 0/1: for example gt0(2)=1 and gt0(-1)=0. But the function ge0(x):=x ≥ 0 outputs True/False (≥ is the html code for "at least"), for example ge0(2)=True and ge0(-3)=False.

Is there some kind of switch that will always give True/False as possible answers?

BTW, Xcas seems to always return True/False

[roadrunner]

I don't know of a switch, but this function returns true and false in CAS:

g2(x):=BEGIN IF x>0 THEN RETURN(true); END ; RETURN(false); END;

In HOME I think you will always get 0 or 1.

-road

[DrD]

If you can tolerate string objects, you could return "True" and "False" in Roads program.

[Alberto Candel]

Thank you. I was looking for something already there, avoiding programming. For my students.

[compsystems]

(01-13-2017 12:06 PM)roadrunner Wrote:  I don't know of a switch, but this function returns true and false in CAS:

g2(x):=BEGIN IF x>0 THEN RETURN(true); END ; RETURN(false); END;

In HOME I think you will always get 0 or 1.

-road

I agree, in HOME should return 1/0 but in CAS MODE always TRUE / FALSE as constants without evaluating.

CASs must show SYMBOLIC and non-numerical values

return PI -> π and not 3.14....
return true -> true and not 1
return false -> false and not 0

To see the numerical value, there are the EVAL commands,

EVAL(TRUE) -> 1