[R] question about matrix

[Mikyoung Jun]

Hello,

I have a few questions about matrix in R. 

Can we make a matrix whose elements are list? I would like to save two
different values in each elements of matrix. If there is a package or
something which can deal with complex numbers, that will do it too. Also,
I am wondering whether there is a function to calculate the rank of the
matrix. I found a matrix package, but it doesn't have functions like that.

Thanks a lot in advance!

Mikyoung Jun