RISK AVERSION, PORTFOLIO DIVERSIFICATION, AND THE DECISION TO GO PUBLIC (...FOR A PRIVATE FIRM...)

Abstract:Risk averse investors should prefer less risky portfolios, all else equal. Markowitz (1952) pioneered the concept of portfolio theory, which launched the modern academic Finance discipline. The idea is that a portfolio that consists of a number of securities has a better mean-variance combination than the same portfolio with just one security. This idea, is essentially behind the development of the modern day capitalism.

EMPIRICAL SIMILARITY AND OBJECTIVE PROBABILITIES

Abstract:We suggest to extend the definition of probability as empirical frequency by the introduction of similarity-weighted frequencies. This formula is axiomatized as follows. A decision maker is asked to express her beliefs by assigning probabilities to certain possible states. We focus on the relationship between her database and her beliefs. We show that, if beliefs given a union of two databases are a convex combination of beliefs given each of the databases, beliefs are a similarity-weighted average of the beliefs induced by each past case.

RATIONALITY IN THE COUNCIL FOR MEDICATIONS AND TECHNOLOGIES, MANDATE AND DELIBERATIONS

Abstract:First, we discuss paradoxes and difficulties in Utilitarian Ethics, especially applied to medical practice and services [Also refer to Mishna, Pirkey Avot bet]. "Cut from A and give to B" is a major difficulty. But as a guide to allocate incremental resources, utilitarian Ethics is unsurpassed: To reduce inequalities, close gaps, maximize cost-benefits.Our main concern is- the national public health basket.Choosing an appropriate measure- say "health years" is important.

ON THE CONFLICT OF CONFLICT OF INTEREST (THE LECTURE WILL BE IN HEBREW)

Abstract:During the last 25 years the Supreme Court acquitted public employees (elected or appointed) from corruption related offenses (bribery and/or breach of public trust) one after the other. These acquittals were (and still are) perceived, both by the Court and the prosecution, as evidence based acquittals. Usually, the Court reasoned its decisions by pointing at some lack of evidence with regard to the mental element of the offence. I would like to suggest a different reading of these cases.

AN ECONOMIC INDEX OF RISKINESS (joint work with Roberto Serrano)

Abstract: On March 21, 2004, an article on the front page of the New York Timespresented a picture of allegedly questionable practices in some state-runpension funds. Among the allegations were that these funds often makeunduly risky investments, recommended by consultants who are interestedparties. The concept of "risky investment" is commonplace in financialdiscussions, and seems to have clear conceptual content. But when onethinks about it carefully and tries to pin it down, it is elusive.

n-PLAYER STOCHASTIC GAMES WITH ADDITIVE TRANSITIONS

Abstract: An n-player stochastic game can be seen as a finite collection of n-dimensional matrix games that are being played, one at a time, in an infinite sequence of discrete stages. At each stage the players, who are assumed to have complete information and perfect recall, independently choose their actions. This joint action determines a payoff to each of the players, as well as a transition probability vector according to which the next matrix game will be selected. Here we assume the transitions to be additive (AT), i.e.

COMPLEXITY AND EFFECTIVE PREDICTION (JOINT WORK WITH JOEL SPENCER)

Abstract: Let G = (I,J,g) be a two-person zero-sum game. We examine the two-person zero-sum repeated game G(k,m) in which player 1 and 2 place down finite state automata with k,m states respectively and the payoff is the average per stage payoff when the two automata face off. We are interested in the cases in which player 1 is "smart" in the sense that k is large but player 2 is "much smarter" in the sense that m>>k. Let S(g) be the value of G were the second player is clairvoyant, i.e., would know the player 1's move in advance.

STRATEGIC ASPECTS OF TERRORISM (Joint work with Professor Eva Carceles Poveda)

Abstract: We study a strategic game between a terror organization and a number ofcountries. The countries can differ in the political or economic power, theeffectiveness in fighting the terrorist in its base and the effectiveness inprotecting their soil against terror attacks. In addition, they can differin their vulnerability to terror attacks and the damage it causes as well asin the benefit they obtain from cooperating with each other in the waragainst terror. We first study a static two stage game analytically.

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