Group representation notation question

My lecturer uses the following notation for a few results in representation of finite groups, and I'm just wondering if anyone could explain what the part on the right hand side means please?

$\displaystyle V \cong \overset{N}{\oplus} V_{i}^{\oplus a_{i}$

Re: Group representation notation question

For questions like this, you might want to try

Symbolab - Symbolab Science & Math Search Engine

You can enter Latex into their search field.

They have an Android app too called IDEAL Finder.