Maximum intersection of linear codes and codes equivalent to linear

We consider linear codes in a space over a finite field with the Hamming metric. A code is called pseudolinear if it is the image of a linear code under an isometric transformation of the space. We derive an upper bound $(q-2)M/q$ attainable for $q\geqslant 3$ for the size of the intersection of two different pseudolinear codes of the same size $M$. Bibliogr. 10.