On the Proof of Vanishing Cosmological Constant in String Theory

The proof of 4-dimensional cosmological constant is given for the 10-dimensional supergravity-super-Yang-Mills theory. Supersymmetry is broken at will. The proof is very simple and it is based on the scale invariance of the theory but it assumes a nouvelle interpretation of quantum theory or rather that of Planck constant. Proof utilizes the supergravity-super-Yan-Mills formulation with a possible stringy correction. A purely stringy proof is under consideration.