Matrices

Matrices[{d1,d2}] represents the domain of matrices of dimensions d1×d2.

Matrices[{d1,d2},dom] represents the domain of matrices of dimensions d1×d2, with components in the domain dom.

Matrices[{d1,d2},dom,sym] represents the subdomain of matrices d1×d2 with symmetry sym.

Please visit the official Wolfram Language Reference for more details and examples on core symbols.