{"type":"ScholarlyArticle","title":"Incentive-Compatible Diffusion Combinatorial Auctions","authors":[{"name":"Haotian Zhu","slug":"haotian-zhu","given":"Haotian","family":"Zhu","affiliation":""},{"name":"Miao Li","slug":"miao-li","given":"Miao","family":"Li","affiliation":""},{"name":"Bin Li","slug":"bin-li","given":"Bin","family":"Li","affiliation":""},{"name":"Dengji Zhao","slug":"dengji-zhao","given":"Dengji","family":"Zhao","affiliation":""}],"abstract":"The diffusion auction is an emerging auction model which leverages social networks to recruit more buyers, thereby improving auction revenue and allocation efficiency. Previous studies on diffusion auctions have primarily focused on the single-parameter domain, where each buyer's valuation function is represented by a single private value. However, due to the complex interdependencies between allocations and network structures, few studies have examined the combinatorial auction domain, in which buyers' valuation functions exhibit multidimensionality. In this paper, we fully characterize implementable diffusion mechanisms within the combinatorial auction domain for the first time. Based on the characterization, we identify a class of allocation policies for each of which the optimal payment, namely the one maximizing the seller's revenue, can be derived in closed form. Furthermore, we apply the established theory to design a practical diffusion combinatorial auction, named the Exhausted-Reference Pricing Mechanism, which is incentive-compatible, individually rational, and weakly budget balanced.","doi":"10.24963/ijcai.2026/396","url":"https://ijcai.org/proceedings/2026/396","pdf":"https://ijcai.org/proceedings/2026/0396.pdf","markdown":"https://ijcai.org/proceedings/2026/396.md","bibtex":"https://ijcai.org/proceedings/2026/bibtex/396","volume":{"slug":"2026","title":"Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2026","url":"https://ijcai.org/proceedings/2026/","year":2026,"location":"Bremen, Germany","dates":"15-21 August 2026","editors":"Diego Calvanese","isbn":"978-1-956792-09-6","publisher":"International Joint Conferences on Artificial Intelligence Organization","doi_prefix":"10.24963/ijcai.2026"},"section":"Game Theory and Economic Paradigms","track":"Main Track","number":396,"pages":{"first":3558,"last":3565},"keywords":["Game Theory and Economic Paradigms: Mechanism design","Game Theory and Economic Paradigms: Auctions and market-based systems","Multidisciplinary Topics and Applications: Economics"],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}