The inequality can be strict - there are graphs "G" for which iγ("G") < "γ"("G"). For example, for some integer "n", let "G" be a graph in which the vertices are the rows and columns of an "n"-by-"n" board, and two such vertices are connected if and only if they intersect. The only independent sets are sets of only rows or sets of only columns, and each of them can be dominated by a single vertex (a column or a row), so "iγ"("G")=1. However, to dominate all vertices we need at least one row and one column, so "γ"("G")=2. Moreover, the ratio between "γ"("G") / "iγ"("G") can be arbitrarily large. For example, if the vertices of "G" are all the subsets of squares of an "n"-by-"n" board, then still "iγ"("G")=1, but "γ"("G")="n".