### can't display the inverse of complex matrix

Hi

it seems that Sagemath is able to calculate this matrix inverse, but it is unable to display it.

Maybe someone will explain me why ? it is not easy to find what I do wrong because there is no error message for n=8
an it's ok for n=4

```
#FFT
w=var('w')
n=8
FFT=matrix(SR,n,n)
#show (FFT)
for i in (0..n-1):
for j in (0..n-1):
FFT[i,j]=w^(i*j)
FFTc=1/sqrt(n) *FFT.subs(w=e^(2*I*pi/n))
#show(" FFTc : ",FFTc)
FFTc.change_ring(CC)
show(" FFTc.right_kernel().matrix() : ",FFTc.right_kernel().matrix())
show (" FFTc.determinant() for n =",str(n),": ",FFTc.determinant())
FFTcI=copy(FFTc).inverse()
#show (" FFT w :",FFT)
show (" FFTc with w=e^(2*I*pi/",str(n),") : ",FFTc)
show (" FFTc inverse with w=e^(2*I*pi/",str(n),") : ",FFTcI)
```