# Limits position of new defined large operators

It is possible to introduce new large operators by using the command,

\DeclareMathSymbol {⟨symbol⟩} {\mathop} {⟨sym-font⟩} {⟨slot⟩}

I wonder if it is possible to change their default limits position from the premable.

You can do similarly to what the LaTeX kernel does for \int:

% fontmath.ltx, line 268:
\DeclareMathSymbol{\intop}{\mathop}{largesymbols}{"52}
\def\int{\intop\nolimits}

This exploits the fact that after an Op atom you can have as many \limits, \nolimits or \displaylimits commands as you want and the last one wins.

With amsmath there are more features. For instance \sum is defined as

\DOTSB\sum@\slimits@

where \sum@ takes the role of \intop in the code above. The macro \slimits@ usually means \displaylimits, but with the option nosumlimits it means \nolimits.

Depending on what you want to achieve, you have also \ilimits@ (that's used for integrals).

If your aim is to make sure that \sum always has limits above and below even in inline formula, please, don't pursue it. Your readers will be grateful, see Is there any global settings to add \limits to evey \sum, \bigcup etc?