In a proceeding to stay arbitration, petitioner appeals from an order of the Supreme Court, Kings County, dated May 11, 1971, which denied the application. Order reversed, on the law, without costs, and application granted. Since the demand for arbitration was served by ordinary mail, the method of service did not satisfy the requirements of CPLR 7503 (subd. [c]) that such a demand must be served in the same manner as a summons or by registered or certified mail, return receipt requested. Accordingly, it was null and void and the application to stay arbitration should have been granted. Rabin, P.J., Hopkins, Munder, Latham and Christ, JJ., concur.