I am writing a book and for the sake of simplicity I want to do something as follows.
Coef((-3x^2 +5x -1)(x^2 +1), 2) = -3 -1 = -4
where the first argument represents polynomial expression and the second one represents order of coefficient we want to output.
Is there a conventional function notation that takes a polynomial and order and yields the coefficient corresponding to the order? In other words, is there
Coef-like notation defined by mathematicians?