755,884 research outputs found
Price-Matching Guarantees
Are price-matching guarantees anticompetitive? This paper examines the incentives for price-matching guarantees in markets where information about prices is costly. Under some conditions the conventional explanation of price-matching announcements as facilitating collusion finds support, and is even strengthened. But our model provides an additional explanation for the practice. A price-matching guarantee may be a credible and easily understood means of communicating to uninformed consumers that a firm is low-priced. The credibility of the signal to uninformed consumers is assured by the behaviour of informed consumers. We contrast the testable implications of our model with those of the anticompetitive theories and discuss supportive evidence from an illustrative sample of retailers.
Welfare guarantees for proportional allocations
According to the proportional allocation mechanism from the network
optimization literature, users compete for a divisible resource -- such as
bandwidth -- by submitting bids. The mechanism allocates to each user a
fraction of the resource that is proportional to her bid and collects an amount
equal to her bid as payment. Since users act as utility-maximizers, this
naturally defines a proportional allocation game. Recently, Syrgkanis and
Tardos (STOC 2013) quantified the inefficiency of equilibria in this game with
respect to the social welfare and presented a lower bound of 26.8% on the price
of anarchy over coarse-correlated and Bayes-Nash equilibria in the full and
incomplete information settings, respectively. In this paper, we improve this
bound to 50% over both equilibrium concepts. Our analysis is simpler and,
furthermore, we argue that it cannot be improved by arguments that do not take
the equilibrium structure into account. We also extend it to settings with
budget constraints where we show the first constant bound (between 36% and 50%)
on the price of anarchy of the corresponding game with respect to an effective
welfare benchmark that takes budgets into account.Comment: 15 page
Providing Delay Guarantees in Bluetooth
Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network. In this paper we present a polling mechanism that provides delay guarantees in an efficient manner and we evaluate this polling mechanism by means of simulation. It is shown that this polling mechanism is able to provide delay guarantees while saving as much as possible resources, which can be used for transmission of best effort traffic or for retransmission
Weaker entanglement guarantees stronger entanglement
The monogamy of entanglement is one of the basic quantum mechanical features,
which says that when two partners Alice and Bob are more entangled then either
of them has to be less entangled with the third party. Here we qualitatively
present the converse monogamy of entanglement: given a tripartite pure system
and when Alice and Bob are weakly entangled, then either of them is generally
strongly entangled with the third party. Our result leads to the classification
of tripartite pure states based on bipartite reduced density operators, which
is a novel and effective way to this long-standing problem compared to the
means by stochastic local operations and classical communications. We also
systematically indicate the structure of the classified states and generate
them.Comment: 5 pages, 1 table, 1 figure. The paper has been totally rewritten
according to the comments from editor
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