We study perfect colorings of the Johnson graph in two colors. We give sufficient conditions for a perfect coloring of the Johnson graph to be k-regular and present examples of perfect colorings. The proof of the theorem is in many respects similar to the proof of the result by Etzion and Schwartz [1] on k-regularity of perfect codes.
['I.Yu. Mogilnykh']
On the regularity of perfect 2-colorings of the Johnson graph