  The concept of Euclidean time is proposed which is dual to the usual
Minkowski time. The De Sitter solution is shown to be dual to the anti-De
Sitter solution under the dual transformation in which Euclidean time and
Minkowski time are interchanged. This observation enables us to make a proposal
in which supersymmetry is broken, but the four dimensional cosmological
constant remains zero. An explicit model is proposed in which we calculate the
cosmological constant. The phenomenology based on this model is presented,
including the issue of the quark-lepton-Higgs mass matrix.
