Bounds on sombor index and inverse sum indeg (ISI) index of graph operations

Let $ G $ be a graph with vertex set $ V(G) $ and edge set $ E(G) $. Denote by $ d_G(u) $ the degree of a vertex $ u \in V(G) $. The Sombor index of $ G $ is defined as $ SO(G) = \sum_{uv \in E(G)} \sqrt{d_u^2 + d_v^2} $, whereas, the inverse sum indeg $ (ISI) $ index is defined as $ ISI(G) = \sum_{uv \in E(G)}    \frac{d_{u}d_{v}}{d_{u} + d_{v}}. $ In this paper, we compute the bounds in terms of maximum degree, minimum degree, order and size of the original graphs $ G $ and $ H $ for Sombor and $ ISI $ indices of several graph operations like corona product, cartesian product, strong product, composition and join of graphs.