Some estimates of the inductive dimensions of the union of two sets

We obtain estimates of the small and large inductive dimensions ind and Ind of the union of two sets, outside the class of completely normal spaces. We show that, in the sense of the inductive dimensions ind0 and Ind0 introduced independently by Charalambous and Filippov, a compact completely normal space which is the union of two dense zero-dimensional subspaces can be infinite-dimensional.