I'm learning the DFT (Discrete Fourrier Transform), and came across a mathematical sign, that I didn't understand.
They say (Inverse of DFT Matrix) F^-1 * c = v
And then, there is an equality that I didn't get: 
What does the bar on top of Fn mean? I know for example for the Discrete Cosine Transform DCT, Cn^-1 = Cn^T (Transpose). But for the DFT I don't get the bar on top of Fn.
Can anyone explain please?