The authors would like to thank Cindy Greenwood, Phil Austin, Greg Lewis, Chris Jeffery, and Nicole Marshall for their helpful comments throughout the course of this project, and Peter Imkeller, Cécile Penland, and Prashant Sardeshmukh for helpful comments on an early draft of the manuscript. We also thank the three anonymous referees for comments that improved the paper. Adam Monahan was supported by the University of British Columbia and by the Crisis Points Group of the Peter Wall Institute for Advanced Studies, and Lionel Pandolfo was supported by a grant from the Natural Sciences and Engineering Research Council of Canada.
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