For a subset of a finite p-group, its images span the Frattini quotient precisely when . By the generating property proved in part (ii), this is equivalent to .
If is a minimal generating set of a group, its images must be an irredundant spanning set in the vector space . A linear dependence would express one image using the others; those other images would still span, so the other elements would still generate , a contradiction. Thus the images form a basis. Conversely lifts of a basis generate , and deleting a lift destroys spanning and hence generation.
This proves the Burnside basis theorem, including equality of sizes for every inclusion-minimal generating set of a group:
Inclusion-minimal generating sets of a group need not have equal sizes in arbitrary finite groups; the elementary-abelian Frattini quotient is the essential p-group feature.