Abstract: Many countries have introduced different carbon emission regulations to achieve sustainable development. However, whether to adopt a carbon tax or a carbon cap-and-trade regulations is still controversial. Remanufacturing is an effective strategy for enterprises to cope with resource shortage and environmental pollution. The growing volume of used products has left some Original Equipment Manufacturers (OEMs) with insufficient production capacity to remanufacture on a large scale effectively, instead licensing remanufacturing to a third-party Remanufacturer (TPR) by charging royalty fee. With patent licensing, the implementation of different carbon emission regulations by the government will have an impact on the operations decisions of OEMs and TPRs. The following questions, therefore, are addressed in this paper: in the context of patent licensing, will different carbon emission regulations affect the operations decisions of OEMs and TPRs? What factors will affect the quantity of new and remanufactured products, royalty rate, and profits for both parties? Which regulation is more conducive to promote this kind of authorized remanufacturing, and achieving the purpose of energy conservation and emission reduction? How should policy makers set carbon caps and carbon tax? Stackelberg game models are respectively proposed to determine the optimal decisions of OEM and TPR for three cases, namely, without the constraint of carbon emission regulations, carbon tax and cap-and-trade. The results obtained by three models are compared, and the effects of different carbon emission regulations on the decision-making are analyzed. The following conclusions are obtained: (1) The presence or absence of carbon emission regulations constraints has a greater impact on the quantity of new products, price for collecting used products, price for remanufactured products, royalty fee and profits of OEM and TPR, but less impact on the quantity of remanufactured products. With the implement of carbon emission regulations, OEM can reduce the production cost and carbon emission cost by reducing the quantity of new products and raising the sales price. At the same time, the royalty fee charged to TPR should be appropriately reduced to encourage TPR to increase the quantity of remanufactured products to meet the market demand. (2) The profits of the OEM and TPR under cap-and-trade regulations are the most. The government can give priority to implement this regulation; (3) Carbon cap, carbon trading prices, carbon emissions per unit of new/remanufactured products and carbon tax prices have a great impact on both parties' decision-making and profits. The government should allocate carbon cap reasonably, manage the order of carbon trading market well, and set a reasonable carbon tax; (4) Remanufacturer should be committed to increasing yield rate, the increase of which can improve the profit of OEM and TPR, but the impact on the latter is greater. The results can provide theoretical reference for OEM and TPR to make operational decisions. At the same time, it provides a theoretical basis for the government to formulate a scientific and reasonable carbon emission regulations.

Key words: operations decision-making; re-manufacturing; patent licensing; carbon emission regulation; Stackelberg game