Collective bargaining— The term collective bargaining, used with respect to public employees, supervisory employees, and public employers, means the performance of the mutual obligation of the representative of a public employer and the exclusive representative of public and supervisory employees in an appropriate unit of the employer to meet at reasonable times and to consult and bargain in a good-faith effort to reach agreement with respect to wages, hours, and other terms and conditions of employment affecting such employees and to execute, if requested by either party, a written document incorporating any collective bargaining agreement reached, but the obligation referred to in this paragraph does not compel either party to agree to a proposal or to make a concession (as described in section 8(d) of the National Labor Relations Act (
29 U.S.C. 158(d))).