We study the complexity of winner determination in single-crossing elections under two classic fully proportional representation rules—Chamberlin–Courant’s rule and Monroe’s rule. Winner determination for these rules is known to be NP-hard for unrestricted preferences. We show that for single-crossing preferences this problem admits a polynomial-time algorithm for Chamberlin–Courant’s rule, but...

Judgment aggregation is an abstract framework for studying collective decision making by aggregating individual opinions on logically related issues. Important types of judgment aggregation methods are those of scoring and distance-based methods, many of which can be seen as generalisations of voting rules. An important question to investigate for judgment aggregation methods is how hard it is ...

In this paper, bid determination problems are studied. In particular, the central problems of allocation, acquisition, completion, and arbitrage are defined. The main theoretical result states that bid determination in double-sided auctions—i.e., completion—where goods can be sold as well as bought, is polynomial-time reducible to bid determination in single-sided auctions—i.e., acquisition. Su...

The theory of procurement auctions traditionally assumes that the offered quantity and quality is fixed prior to source selection. Multi-attribute reverse auctions allow negotiation over price and qualitative attributes such as color, weight, or delivery time. They promise higher market efficiency through a more effective information exchange of buyer’s preferences and supplier’s offerings. Thi...

Negotiation events in industrial procurement involving multiple, highly customisable goods pose serious challenges to buyers when trying to determine the best set of providers? offers. Typically, a buyer?s decision involves a large variety of constraints that may involve attributes of a very same item as well as attributes of different, multiple items. In this paper we present the winner determ...

The theory of procurement auctions traditionally assumes that the offered quantity and quality is fixed prior to source selection. Multi-attribute reverse auctions allow negotiation over price and qualitative attributes such as color, weight, or delivery time. They promise higher market efficiency through a more effective information exchange of buyer’s preferences and supplier’s offerings. Thi...

Internet search results are a growing and highly profitable advertising platform. Search providers auction advertising slots to advertisers on their search result pages. Due to the high volume of searches and the users’ low tolerance for search result latency, it is imperative to resolve these auctions fast. Current approaches restrict the expressiveness of bids in order to achieve fast winner ...

Combinatorial auctions are currently becoming a common practice in industrial procurement, allowing bidders (sellers of goods and services in the procurement setting) to avoid the risk of selling good or service bundles that are incomplete, inefficient, or excessively expensive to deliver. Two major concerns in combinatorial auction design are the revelation or discovery of market price informa...

Negotiation events in industrial procurement involving multiple, highly customisable goods pose serious challenges to buyers when trying to determine the best set of providers’ offers. Typically, a buyer’s decision involves a large variety of constraints that may involve attributes of a very same item as well as attributes of different, multiple items. In this paper we present the winner determ...

During the past few years, auctions have become popular in conducting trade negotiations on the Internet. The design of new auctions and other negotiation protocols has become an important topic for both, industry and academia. Traditional auction mechanisms allow price-only negotiations for which the winner determination is a computationally simple task. However, the need for new auction mecha...