Zsolt Katona

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Vol. XLVIII (June 2011), 425 –443 *Zsolt Katona is Assistant Professor of Marketing, Haas School of Business, University of California, Berkeley (e-mail: zskatona@haas.berkeley. edu). Peter Pal Zubcsek is Assistant Professor of Marketing, University of Florida (e-mail: pzubcsek@ufl.edu). Miklos Sarvary is Professor of Marketing, INSEAD (e-mail:(More)
Paid placements on search engines reached sales of over $10 billion in the U.S. last year and represent the most rapidly growing form of online advertising today. In its classic form, a search engine sets up an auction for each search word in which competing web sites bid for their sponsored links to be displayed next to the search results. We model this(More)
We model the commercial World Wide Web as a directed graph emerging as the equilibrium of a game in which utility maximizing Web sites purchase (advertising) in-links from each other, while also setting the price of these links. In equilibrium, higher content sites tend to purchase more advertising links (mirroring the Dorfman-Steiner rule) while selling(More)
Let [n] denote the set {1, 2, ..., n}, 2 the collection of all subsets of [n] and F ⊂ 2 be a family. The maximum of |F| is studied if any r subsets have an at least s-element intersection and there are no ` subsets containing t+1 common elements. We show that |F| ≤ Pt−s i=0 n−s i + t+`−s t+2−s n−s t+1−s + `− 2 and this bound is asymptotically the best(More)
A de ning property of the World Wide Web is a content site's ability to place virtually costless hyperlinks to third-party content as a substitute or complement to its own content. Costless hyper-linking has enabled new types of players, usually referred to as content aggregators, to successfully enter content ecosystems, attracting tra c and revenue by(More)
Advertisers who run online advertising campaigns often utilize multiple publishers concurrently to deliver ads. In these campaigns advertisers predominantly compensate publishers based on effort (CPM) or performance (CPA) and a process known as Last-Touch attribution. Using an analytical model of an online campaign we show that CPA schemes cause(More)
Let F be a family of an n-element set. It is called intersecting if every pair of its members have a non-disjoint intersection. It is wellknown that an intersecting family satisfies the inequality |F| ≤ 2n−1. Suppose that |F| = 2n−1+i. Choose the members of F independently with probability p (delete them with probability 1−p). The new family is intersecting(More)
Let H denote the set {f1, f2, ..., fn}, 2 the collection of all subsets of H and F ⊆ 2 be a family. The maximum of |F| is studied if any k subsets have a non-empty intersection and the intersection of any l distinct subsets (1 ≤ k < l) is empty. This problem is reduced to a covering problem. If we have the conditions that any two subsets have a non-empty(More)
Let f(l,t,n) be the maximal size of a family F ⊂ 2[n] such that any l ≥ 2 sets of F have an exactly t ≥ 1-element intersection. If l ≥ 3, it trivially comes from [8] that the optimal families are trivially intersecting (there is a t-element core contained by all the members of the family). Hence it is easy to determine f(l, t, n) = ⌊ l 2(n− 1) ⌋ +1. Let(More)