Ah! Of course. Actually, I recently realized that I should treat symbolic coefficients as polynomials with integer coefficient 1.
Thanks Ralf! On Mon, May 28, 2018 at 10:03 AM, Ralf Hemmecke <[email protected]> wrote: > On 05/28/2018 08:53 AM, Marduk wrote: > > Dear all, > > > > As the following example shows, when writing polynomials with > noncommutative > > variables one has to specify that the symbols belong to the list of NC > > variables: > > > > ops := OVAR[A,B] > > > > ncomm := XDPOLY(ops, Integer) > > > > q : ncomm := 3*B::ops*A::ops > > > > > > I just found out that doing the same in REDUCE is more pleasant, since > one > > can > > tell the interpreter that some identifiers are to be treated as > > noncommuting variables: > > > > nc_setup({A,B}); > > > > A*B - B*A; > > > > > > How could one achieve the same with FriCAS? > > Just don't compute with symbols. Turn the symbols A and B into elements > of the respective domain, i.e. make them noncommutative polynomials. > > ls: List Symbol := ["a"::Symbol, "b"::Symbol] > ops := OrderedVariableList ls > NPol := XDistributedPolynomial(ops, Fraction Integer) > vars :=[index(i)$ops::NPol for i in 1..#ls] > a := vars.1 > b := vars.2 > a*b - b*a > > Note that instead of > > "a"::Symbol > > you can also simply write > > 'a > > That notation seems to be influenced by LISP and denotes the VALUE > > of a symbol with name a. > > As long as the programming variable a is unassigned in the current > session, you can also simply write a and the interpreter will try to > figure out would you could have meant by it. With > > "a"::Symbol > > however, there is no doubt. > > Enjoy. > > Ralf > > -- > You received this message because you are subscribed to a topic in the > Google Groups "FriCAS - computer algebra system" group. > To unsubscribe from this topic, visit https://groups.google.com/d/ > topic/fricas-devel/LSB-lm50bgU/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/fricas-devel. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.
