Int. J. Operational Research, Vol. 16, No. 1, 2013 1 A vendor–buyer integrated production-inventory model with quantity discount and unequal sized shipments B.C. Giri* and B. Roy Department of Mathematics, Jadavpur University, Kolkata 700 032, West Bengal, India E-mail: bibhas_pnu@yahoo.com E-mail: roy.balaji86@gmail.com *Corresponding author Abstract: This paper considers a single-vendor single-buyer integrated production-inventory model for a single product. The vendor offers a quantity discount to motivate the buyer to buy more quantities and he delivers the buyer’s order quantity in a number of unequal sized shipments. The proposed model is formulated and the optimal decisions are obtained by minimising the average total cost of the integrated system. A numerical example is taken to illustrate the developed model. Keywords: inventory; vendor–buyer; quantity discount; unequal shipments. Reference to this paper should be made as follows: Giri, B.C. and Roy, B. (2013) ‘A vendor-buyer integrated production-inventory model with quantity discount and unequal sized shipments’, Int. J. Operational Research, Vol. 16, No. 1, pp.1–13. Biographical notes: B.C. Giri is an Associate Professor in the Department of Mathematics, Jadavpur University, Kolkata, India. He did his MS in Mathematics and PhD in Operations Research both from Jadavpur University, Kolkata, India. His research interests include supply chain management, inventory theory, production planning and scheduling, reliability and maintenance. He has published papers in Naval Research Logistics, Int. J. Production Research, OMEGA, Journal of the Operational Research Society, European Journal of Operational Research, Int. J. Production Economics, etc. He was a JSPS Research Fellow at Hiroshima University, Japan during the period 2002–2004 and Humboldt Research Fellow at Mannheim University, Germany during the period 2007–2008. B. Roy is a Junior Research Fellow in the Department of Mathematics, Jadavpur University, Kolkata, India. He did his BS and MS in Mathematics from Jadavpur University. His area of interest is inventory/supply chain management. Copyright © 2013 Inderscience Enterprises Ltd.