Hi, professor:

I defined a matrix variable as follows:

**variable Y(nx*N,6)**

where **nx**=6, **N**=10. I want to constraint the block matrix of Y to a symmetric matrix, i,e,

**Y**(**nx**(k-1)+1:**nx***k,1:6), k=1,…,N, is a symmetric matrix. How do I express it in CVX?

Besides, the keyword *semidefinite* in CVX means *positive semidefinite*?

Thank you very much.

Try

```
variable Y(6,6,N);
...
Y==permute(Y,[2 1 3]);
```

and yes, semidifinite in CVX means positive semidefinete.

Thanks for your reply.I doubt that the block matrix of Y is symmetric after this operation.

Besides, another question, is the following expression legal in CVX?

variable **P**(6,6,N) *semidefinite*

`P(6,6,N) senidefinite`

is allowed in CVX and makes each 6 by 6 slice of the 6 by 6 by N array a symmetric positive semidefinite matrix.

thank you very much!!