Assume facility with functions, Assume and functional forms (11.2.97)

Mark S. Broski

Is it possible for the assume facility to recognize functional forms?

For instance,

assume (f(t)>0)

is(f(t)>0)

gives the result TRUE

but if I enter

is(f(t)+f(t)>0)

an error code is returned.

Robert Israel

Not an error code, but FAIL (indicating Maple doesn’t know) in Release 3. This particular problem is fixed in Release 4:

> is(f(t)+f(t)>0); 
                            true

However, assuming f(t) > 0 doesn’t say anything about f(x), or any other value of the function except literally f(t).

> is(f(x)>0); 
                         FAIL

Ideally you’d like to be able to say

> assume(f>0);

But this doesn’t work:

> is(f(x)>0); 
                        FAIL

Brian Blank

I note that Robert Israel has already given a response to the question as asked. Perhaps the following constructive workaround might be of some use to you: