Reverse of a univariate polynomial #
reflect N f is the polynomial such that
(reflect N f).coeff i = f.coeff (revAt N i).
In other words, the terms with exponent
[0, ..., N] now have exponent
[N, ..., 0].
reflect is only used when
N is at least as large as the degree of
Eventually, it will be used with
N exactly equal to the degree of