Infinite-Duration Bidding Games

Two-player games on graphs are widely studied in formal methods as they model the interaction between a system and its environment. The game is played by moving a token throughout a graph to produce an infinite path. There are several common modes to determine how the players move the token through the graph; e.g., in turn-based games the players alternate turns in moving the token. We study the {\em bidding} mode of moving the token, which, to the best of our knowledge, has never been studied in infinite-duration games. The following bidding rule was previously defined and called Richman bidding. Both players have separate {\em budgets}, which sum up to $1$. In each turn, a bidding takes place: Both players submit bids simultaneously, where a bid is legal if it does not exceed the available budget, and the higher bidder pays his bid to the other player and moves the token. The central question studied in bidding games is a necessary and sufficient initial budget for winning the game: a {\em threshold} budget in a vertex is a value $t \in [0,1]$ such that if Player $1$'s budget exceeds $t$, he can win the game, and if Player $2$'s budget exceeds $1-t$, he can win the game. Threshold budgets were previously shown to exist in every vertex of a reachability game, which have an interesting connection with {\em random-turn} games -- a sub-class of simple stochastic games in which the player who moves is chosen randomly. We show the existence of threshold budgets for a qualitative class of infinite-duration games, namely parity games, and a quantitative class, namely mean-payoff games. The key component of the proof is a quantitative solution to strongly-connected mean-payoff bidding games in which we extend the connection with random-turn games to these games, and construct explicit optimal strategies for both players.Comment: A short version appeared in CONCUR 2017. The paper is accepted to JAC

Homeownership and Unemployment Duration

We examine the effects of homeownership on individuals' unemployment durations in the USA. We take into account that an unemployment spell can terminate with a job or with a non-participation transition. The endogeneity of homeownership is addressed through the estimation of a full maximum likelihood function which jointly models the competing hazards and the probability of being a homeowner. Unobserved factors contributing to the probability of being a homeowner are allowed to be correlated with unobservable heterogeneity in the hazard rates. We find that unemployed homeowners are less likely to find a job than renters. The effect is small but statistically significant for most specifications. The effect is stronger for outright owners and weaker for mortgage holders. We also find that outright owners have a higher and mortgage holders a lower probability of exiting to non-participation than renters

Article XV: Duration and Withdrawal

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Duration and Risk

Duration has long been used as a means of managing the risk of bond portfolios. It has also been extended to the analysis of equities. Although it is often been compared with the half-life of an asset it is more correct to consider duration as the approximate percentage change in price for each one-percent change in yield. Given this view it will be seen that the volatility of an asset and its duration are closely related. This paper uses the duration of a conventional valuation model to estimate both the volatility and total risk of the each sector of the UK commercial property market relative to the property market as a whole. The approach has potential value in estimating the risk of a new property where historic time series information is either limited on not available. In addition, by drawing a distinction between ex-post and ex-ante measures of risk the paper also estimates the inflation flow through rate for different lease structures.

Vowel duration issue in Civili

The main goal of this article is to define the problem of vowel duration in Civili (H12a). It shows that the so-called Civili vowel-length desperately needs to be re-examined, because previous works on the sound system of this language hardly explain a number of phonological phenomena, such as vowel lengthening, on the basis of data at hand. Demonstrating the problem in question, the author first reviews previous works that all identify a vowel lengthening in Civili. From different analyses the complexity of the phenomenon is found out by observing differences from an analysis to another, and by regarding difficulties the different phonologists came up against. Then, the problem is also seen through the weakness of each analysis results. This eventually shows more aspects of the vowel duration issue, and leads the author to make a clear distinction between vowel length and vowel lengthening that can be all regarded as only vowel duration. Finally, the article shares a possible way for a solution through an experimental approach of the Civili sound system

Estimating Unemployment Duration

macroeconomics, unemployment

Risk and duration

Interest rates ; Government securities ; Risk