**Note:** You are looking at a static copy of the former PineWiki site, used for class notes by James Aspnes from 2003 to 2012. Many mathematical formulas are broken, and there are likely to be other bugs as well. These will most likely not be fixed. You may be able to find more up-to-date versions of some of these notes at http://www.cs.yale.edu/homes/aspnes/#classes.

The FischerLynchPaterson impossibility result for asynchronous consensus with one crash failure. Readings: Chapter 12 gives the shared-memory version of the proof (originally due to Loui and Abu-Amara, based on the FLP result); we did the message-passing version from the original FLP paper, which can be found here.