Abstract

The sets of vertical vectors in the contingent cone, the intermediate tangent cone and the Clarke tangent cone to the graph of a multifunction between normed spaces at a given point are estimated or computed by exact formulae under some suitable assumptions. The obtained results sharpen and complement the results of \textit{H. D. Dien} and \textit{N. D. Yen} [Acta Math., Vietnam. 10, No. 1, 144–147 (1985; Zbl 0611.47041)] where the set of vertical vectors in the Clarke tangent cone was considered.