Published online by Cambridge University Press: 20 November 2018
In 1945, L. I. Kopejkina (4), at the suggestion of A. G. Kurosh, began a programme of studying the properties of free projective planes and the analogies between free planes and free groups. In this paper, this study will be extended by proving a tool theorem and several of its consequences. The theorem deals with the existence of "minimal free generators" for subplanes of free planes.
A set of points and lines and an incidence relation are said to form a projective plane if the following three axioms are satisfied.