More exactly is...
I'm trying to understand the following worked problem:
So, . And did they subtract from to get because the result had degree 4? Does this mean every time the degree gets larger than or equal to 4, we must subtract m(x) from it (to have everything in mod m(x))?
it IS kind of confusing because when the author says " " what he really means is:
is the coset of x+1 in K. and in K, multiples of m(x) are set equal to 0.
so in K, (remembering "x" in K is really x + m(x)),
(more precisely, the coset is the same coset as , since
, the identity of
with this (unfortunately standard) abuse of notation:
(since 4 is a power of 2, the and terms are all 0)