Commutators spanning the matrices

[hkus10]

Let T be the set of all matrics of the form AB - BA, where A and B are nxn matrics. Show that span T is not Mnn.

1) does "span T is not Mnn" mean that Mnn does not span T?

Thanks

 

[Char. Limit]

Looks to me like what it means is that T does not span Mnn, not the other way around.