Which topic(s) does this matrix come from? What is the name of this matrix?
$\pmatrix{1&1&1\\1&\omega&\omega^2\\1&\omega^2&\omega}$
Which topic(s) does this matrix come from? What is the name of this matrix?
$\pmatrix{1&1&1\\1&\omega&\omega^2\\1&\omega^2&\omega}$
This is the discrete Fourier transform matrix of size $3$. It naturally appears mathematically in the representation theory (don't be intimidated by this!) of the cyclic groups $\mathbb{Z}/n\mathbb{Z}$, as well as practically in signal processing and related fields.