The special rank of virtual knot groups

Abstract

In this paper we introduce the special rank for virtual knots and some properties of this number are studied. Although we do not know if it can be considered as a nontrivial extension of the meridional rank given by [H. U. Boden and A. I. Gaudreau, Bridge number for virtual and welded knots, J. Knot Theory Ramifications 24 (2015), Article ID: 1550008] and by [M. Boileau and B. Zimmermann, The [Formula: see text]-orbifold group of a link, Math. Z. 200 (1989) 187–208], we prove that classical knots with special rank [Formula: see text] are [Formula: see text]-bridge knots. Therefore, a modified version of the so called Cappell and Shaneson conjecture could be considered.