New directions in mechanism design

Mechanism design uses the tools of economics and game theory to design rules of interaction for economic transactions that will,in principle, yield some de- sired outcome. In the last few years this field has received much interest of researchers in computer science, especially with the Internet developing as a platform for communications and connections among enormous numbers of computers and humans. Arguably the most positive result in mechanism de- sign is truthful and there are only one general truthful mechanisms so far : the generalized Vickrey-Clarke-Groves (VCG) mechanism. But VCG mecha- nism has one shortage: The implementation of truthfulness is on the cost of decreasing the revenue of the mechanism. (e.g., Ning Chen and Hong Zhu. [1999]). We introduce three new characters of mechanism:partly truthful, criti- cal, consistent, and introduce a new mechanism: X mechanism that satisfy the above three characters. Like VCG mechanism, X mechanism also generalizes from Vickery Auction and is consistent with Vickery auction in many ways, but the extended methods used in X mechanism is different from that in VCG mechanism . This paper will demonstrate that X mechanism better than VCG mechanism in optimizing utility of mechanism, which is the original intention of mechanism design. So partly truthful,critical and consistent are at least as important as truthful in mechanism design, and they beyond truthful in many situations.As a result, we conclude that partly truthful,critical and consistent are three new directions in mechanism design

Depth-graded motivic Lie algebra

Consider the neutral Tannakian category mixed Tate motives over Z, in this paper we suggest a way to understand the structure of depth-graded motivic Lie subalgebra generated by the depth one part. We will show that from an isomorphism conjecture proposed by K. Tasaka we can deduce the F. Brown matrix conjecture and the non-degenerated conjecture about depth-graded motivic Lie subalgebra generated by the depth one part.Comment: 13 page

The depth structure of motivic multiple zeta values

In this paper, we construct some maps related to the motivic Galois action on depth-graded motivic multiple zeta values. And from these maps we give some short exact sequences about depth-graded motivic multiple zeta values in depth two and three. In higher depth we conjecture that there are exact sequences of the same type. And we will show from three conjectures about depth-graded motivic Lie algebra we can nearly deduce the exact sequences conjectures in higher depth. At last we give a new proof of the result that the modulo zeta(2)$ version motivic double zeta values is generated by the totally odd part. And we reduce the well-known conjecture that the modulo zeta (2) version motivic triple zeta values is generated by the totally odd part to an isomorphism conjecture in linear algebra.Comment: 25 page

Approximate Message Passing with Unitary Transformation

Approximate message passing (AMP) and its variants, developed based on loopy belief propagation, are attractive for estimating a vector x from a noisy version of z = Ax, which arises in many applications. For a large A with i. i. d. elements, AMP can be characterized by the state evolution and exhibits fast convergence. However, it has been shown that, AMP mayeasily diverge for a generic A. In this work, we develop a new variant of AMP based on a unitary transformation of the original model (hence the variant is called UT-AMP), where the unitary matrix is available for any matrix A, e.g., the conjugate transpose of the left singular matrix of A, or a normalized DFT (discrete Fourier transform) matrix for any circulant A. We prove that, in the case of Gaussian priors, UT-AMP always converges for any matrix A. It is observed that UT-AMP is much more robust than the original AMP for difficult A and exhibits fast convergence. A special form of UT-AMP with a circulant A was used in our previous work [13] for turbo equalization. This work extends it to a generic A, and provides a theoretical investigation on the convergence.Comment: 5 page

On the structure of zero-sum free set with minimum subset sums in abelian groups

Let $G$ be an additive abelian group and $S\subset G$ a subset. Let $\Sigma(S)$ denote the set of group elements which can be expressed as a sum of a nonempty subset of $S$. We say $S$ is zero-sum free if $0 \not\in \Sigma(S)$. It was conjectured by R.B.~Eggleton and P.~Erd\"{o}s in 1972 and proved by W.~Gao et. al. in 2008 that $|\Sigma(S)|\geq 19$ provided that $S$ is a zero-sum free subset of an abelian group $G$ with $|S|=6$. In this paper, we determined the structure of zero-sum free set $S$ where $|S|=6$ and $|\Sigma(S)|=19$.Comment: 19 page

On the unsplittable minimal zero-sum sequences over finite cyclic groups of prime order

Let $p > 155$ be a prime and let $G$ be a cyclic group of order $p$. Let $S$ be a minimal zero-sum sequence with elements over $G$, i.e., the sum of elements in $S$ is zero, but no proper nontrivial subsequence of $S$ has sum zero. We call $S$ is unsplittable, if there do not exist $g$ in $S$ and $x,y \in G$ such that $g=x+y$ and $Sg^{-1}xy$ is also a minimal zero-sum sequence. In this paper we show that if $S$ is an unsplittable minimal zero-sum sequence of length $|S|= \frac{p-1}{2}$, then $S=g^{\frac{p-11}{2}}(\frac{p+3}{2}g)^4(\frac{p-1}{2}g)$ or $g^{\frac{p-7}{2}}(\frac{p+5}{2}g)^2(\frac{p-3}{2}g)$. Furthermore, if $S$ is a minimal zero-sum sequence with $|S| \ge \frac{p-1}{2}$, then \ind(S) \leq 2.Comment: 11 page

Motivic multiple zeta values reletive to \mu_2

We establish a short exact sequence about depth-graded motivic double zeta values of even weight relative to $\mu_2$. We find a basis for the depth-graded motivic double zeta values relative to $\mu_2$ of even weight and a basis for the depth-graded motivic triple zeta values relative to $\mu_2$ of odd weight. As an application of our main results, we prove Kaneko and Tasaka's conjectures about the sum odd double zeta values and the classical double zeta values. We also prove an analogue of Kaneko and Tasaka's conjecture in depth three. At last we formulate a conjecture which is related to sum odd multiple zeta values in higher depth.Comment: 27 page

Motivic double zeta values of odd weight

For odd $N\geq 5$, we establish a short exact sequence about motivic double zeta values $\zeta^{\mathfrak{m}}(r,N-r)$ with $r\geq3$ odd, $N-r\geq2$. From this we classify all the relations among depth-graded motivic double zeta values $\zeta^{\mathfrak{m}}(r,N-r)$ with $r\geq3$ odd, $N-r\geq2$. As a corollary, we confirm a conjecture of Zagier on the rank of a matrix which concerns relations among multiple zeta values of odd weight.Comment: 15 page

Strategically Simple Mechanisms

We define and investigate a property of mechanisms that we call "strategic simplicity," and that is meant to capture the idea that, in strategically simple mechanisms, strategic choices require limited strategic sophistication. We define a mechanism to be strategically simple if choices can be based on first-order beliefs about the other agents' preferences and first-order certainty about the other agents' rationality alone, and there is no need for agents to form higher-order beliefs, because such beliefs are irrelevant to the optimal strategies. All dominant strategy mechanisms are strategically simple. But many more mechanisms are strategically simple. In particular, strategically simple mechanisms may be more flexible than dominant strategy mechanisms in the bilateral trade problem and the voting problem

Computer Network Reliability Optimization Calculation Based on Genetic Algorithm

How to effectively reduce the network node link cost by improving the reliability of computer network transmission system is one of the important targets of computer network reliability optimization calculation. Therefore, in the computer network reliability optimization calculation, it is necessary to integrate the computer network link medium cost, network reliability optimization mathematical model and other factors. This paper describes genetic algorithm and its implementation process, as well as the application of genetic algorithm to the network link cost and network reliability optimization calculation. In addition, it is indicated from the simulation results that genetic algorithm can effectively solve the reliability optimization calculation problem which is difficult to solve by the traditional algorithm of network, so as to speed up the calculation speed of computer network and optimize the network calculation result