From dd13f5b0d7afd397b5207a4b5994c8e61ed97163 Mon Sep 17 00:00:00 2001 From: Paul Date: Mon, 15 Dec 2014 18:59:46 -0500 Subject: Added stuff --- project2/main.tex | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) (limited to 'project2') diff --git a/project2/main.tex b/project2/main.tex index dc863df..96a1d6b 100644 --- a/project2/main.tex +++ b/project2/main.tex @@ -22,6 +22,13 @@ \setlength{\itemsep}{-1ex} \setlength{\parsep}{0pt}}% {\end{description}} +\newcommand\blfootnote[1]{% + \begingroup + \renewcommand\thefootnote{}\footnote{#1}% + \addtocounter{footnote}{-1}% + \endgroup +} + \DeclareMathOperator*{\E}{\mathbb{E}} \let\Pr\relax \DeclareMathOperator*{\Pr}{\mathbb{P}} @@ -37,14 +44,15 @@ \author{Thibaut Horel \and Paul Tylkin} \title{Economics 2099 Project} - \begin{document} \maketitle + + \section{Introduction} -We consider the problem of selling $m$ heterogeneous items to a single agent +\blfootnote{We are deeply grateful to Jason Hartline who provided the original idea for this project.}We consider the problem of selling $m$ heterogeneous items to a single agent with additive utility. The type $t$ of the agent is drawn from a distribution $F$ over $\R_+^m$. For an allocation $x = (x_1,\ldots,x_m)$ where $x_i$, $i\in[m]$, denotes the probability of being allocated item $i$ and payment $p$, @@ -99,9 +107,10 @@ $\hat{x}$. To provide some more intuition about this, we assume that the buyer is charged a price $p_0$ to participate in the mechanism, and then is offered a menu of goods with prices $p_1,...,p_m$. The buyer's utility over the goods is additive, as above. However, there is an ex-ante constraint of being allocated a given good $i$, given by $\hat{x}_i$. For each good, if the buyer is allocated the good, which he is with probability $x_i \leq \hat{x}_i$, then he pays $p_i$; otherwise, he pays nothing. This is essentially the concept of a two-part tariff, as discussed in \cite{armstrong}. + -Let us denote by $R(\hat{x})$ the revenue obtained by the optimal mechanism -solution to Problem~\ref{eq:opt} with ex-ante allocation constraint +We use the notation from \cite{alaei} where $R(\hat{x})$ denotes the revenue obtained by the optimal mechanism +solution to Problem~\ref{eq:opt} with ex-ante allocation constraint $\hat{x}$. \eqref{eq:ea}. \paragraph{Problem.} \emph{Given an ex-ante allocation constraint $\hat{x}$, is @@ -123,12 +132,12 @@ answer to our problem: \item when $\hat{x} = (1,\ldots,1)$, \eqref{eq:ea} does not further constrain Problem~\ref{eq:opt}, i.e. the constraint is trivially satisfied. In this case, as discussed above, the - mechanism described in \cite{babaioff} provides a 6-approximation. - \item when $\hat{x} = (\frac{1}{m},\ldots,\frac{1}{m})$, by summing the + mechanism described in \cite{babaioff} provides a 6-approximation to $R((1,...,1))$. + \item when $\hat{x} = \left(\frac{1}{m},\ldots,\frac{1}{m}\right)$, by summing the constraint \eqref{eq:ea} for all $i\in[m]$, we see that the ex-ante allocation constraint implies that in expectation, no more than one-item is sold to the agent. This is exactly the unit-demand case for - which TODO:cite provides a 2 approximation. + which TODO:cite provides a 2 approximation to $R\left( \left(\frac{1}{m},\ldots,\frac{1}{m}\right)\right)$. \end{itemize} \section{Related Work} -- cgit v1.2.3-70-g09d2