let M_n(c)Let $M_n(\mathbb{C})$ denote the n times n matrices over the complex number field. N be a subspace of
M_n(C) $M_n(\mathbb{C})$.
ifIf all the matrices in N are non-invertible , what is the maximum of the dimension of N can be?
ifIf all the matrices in N commute with each other , what is the maximum of the dimension of N can be?
ifIf all the matrices in N are nilpotent , what is the maximum of the dimension of N can be?
ifIf all the non-zero matrices in N are invertible , what is the maximum of the dimension of N can be?