(1) Department of Mathematics, University of Ulsan, Ulsan, 680-749, Korea;(2) Department of Mathematics, University of Ulsan, Ulsan, 680-749, Korea
Abstract:
Let N be a simply connected 2-step nilpotent Lie group equipped with a left-invariant metric. We consider the characterizations of Jacobi fields and conjugate points along geodesics emanating from the identity element in N. We obtain a partial result for N and the complete result for N with a one-dimensional center.