Stopping the spread

The spread option optimal stopping game

We present a solution to an optimal stopping game for geometric Brownian motion with gain functions having the form of payoff functions of spread options. The method of proof is based on reducing the initial problem to a free-boundary problem and solving the latter by means of the smooth-fit principle. The derived result can be interpreted as pricing the (perpetual) spread game option in the Bl...

Stopping short the spread of methicillin-resistant Staphylococcus aureus.

A s described by Andrew Simor and colleagues 1 elsewhere in this issue (page 21), Canadian hospitals, like many hospitals elsewhere, have recently witnessed an increase in the proportion of Staphylococcus aureus isolates that are resistant to methicillin (known as methi-cillin-resistant S. aureus or MRSA). The rate has risen from 1% of all isolates in 1995 to 6% in 1999. 1 Despite the increase ...

Ending Child Marriage and Stopping the Spread of HIV

Stopping the Rot

In July 2000, the fi nger of blame for a mysterious mass killer of Californian oak trees came to rest on a previously undescribed plant pathogen. From the initial identifi cation of Phytophthora ramorum, it took less than four years to produce a draft sequence of its genome, one of the fastest-ever discovery-to-sequence stories for a complex pathogen. This achievement was a United States initia...

Non Stopping times and Stopping Theorems

Given a random time, we give some characterizations of the set of martingales for which the stopping theorems still hold. We also investigate how the stopping theorems are modified when we consider arbitrary random times. To this end, we introduce some families of martingales with remarkable properties. DOI: https://doi.org/10.1016/j.spa.2006.06.005 Posted at the Zurich Open Repository and Arch...