Andriy

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12 years, 63 days

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These are questions asked by Andriy

Hi. I need to test if a variable is a dot-product of "anything"-s (usually it is quantum operators).
I try the following

restart; 
with(Physics);
Physics:-Setup(mathematicalnotation = true);
Physics:-Setup(anticommutativeprefix = psi);
ap1 := Physics:-Creation(psi, 1, notation = explicit);
am1 := Physics:-Annihilation(psi, 1, notation = explicit);
ap2 := Physics:-Creation(psi, 2, notation = explicit);
am2 := Physics:-Annihilation(psi, 2, notation = explicit);

z1 := ap1.am1.ap2:
type(z1, ('`.`')(anything));

and get

false

whereas

z2 := a*b*c; 
type(z2, (':-`*`')(anything));

returns

true

I studied ?type,structured and other sources but didn't find any answer.

Hello
Is there a Maple-function that returns a number of transpositions needed to transform a list into a list with some particular order? Actually, I need just a parity of a number of transpositions. All elements of a list are different.

For example, one needs 4 (even) transpositions to transform a list [w,x,y,z] into a list [y,x,z,w]:
[w,x,y,z]->[w,y,x,z]->[y,w,x,z]->[y,x,w,z]->[y,x,z,w]

Thank you

I am trying the following:

restart; 
with(Physics);
with(Library);
Setup(mathematicalnotation = true);
Setup(op = A);
assume(n::integer);

type(A^n, Physics:-`^`(PhysicsType:-ExtendedQuantumOperator, integer));
type(A^n, PhysicsType:-ExtendedQuantumOperator^integer);

the result is

false
false

However, I expected to get true in both cases. How to construct correct type for A^n?
Thank you.

I do the following:

restart; 
z := x + y;
type(z, specfunc(name, `+`));

However the result is 'false'. How to correct my type checking?

Hi
I am trying to define commutation rules between operators a1, a2, b1, b2.


restart;
with(Physics);
with(Library);
Setup(mathematicalnotation = true);

Setup(op = {a1, a2, b1, b2});
alias(A = %AntiCommutator);
algebra := [A(a1, a1) = 0, A(a2, a2) = 0, A(a1, a2) = 0, A(b2, a1) = 0, A(a1, b1) = 1,
A(a2, b2) = 1];
Se
tup(algebrarules = algebra);

However, the command Setup(algebrarules = algebra); causes an error. What is wrong? Noteworthy that if commutator is considered instead of anticommutator alias(A = %Commutator); then correct result follows.
Thank you.

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