Collective bargaining is the performance of the mutual obligation of the public employer and the representative of the public employes to meet at reasonable times and confer in good faith with respect to wages, hours and other terms and conditions of employment, or the negotiation of an agreement or any question arising thereunder and the execution of a written contract incorporating any agreement reached but such obligation does not compel either party to agree to a proposal or require the making of a concession.
43 P.S. § 1101.701