Arrays
Arrays[{d1,…,dr}] represents the domain of arrays of rank r and dimensions di.
Arrays[{d1,…,dr},dom] represents the domain of arrays of dimensions di, with components in the domain dom.
Arrays[{d1,…,dr},dom,sym] represents the subdomain of arrays with dimensions di and symmetry sym.
Please visit the official Wolfram Language Reference for more details and examples on core symbols.