Basically, can I get this
Rather than what \[ \sum_{A \subset E} () \] yields? That is I want the equation not inline but also not have the subscript under a summation in order to save space. I know you can use \Sigma instead but I'm told that \Sigma is smaller than \sum

\Sigmato create a summation symbol. Not only do\Sigmaand\sumlook quite different, they also have different math status values --\Sigmais math-ord, whereas\sumismath-op`. This affects the ability to typeset limits of summation. – Mico Apr 10 '22 at 06:37