Freely Generated Projective Planes with Finite Computable Dimension

Аннотация

It is proved that for every natural n ≥ 1, there exists a computable freely generated projective plane with computable dimension n. It is stated that the class of freely generated projective planes is complete with respect to degree spectra of automorphically nontrivial structures, effective dimensions, expansions by constants, and degree spectra of relations.