Alda and Carlos presented their work on Disjunctive Short sums. They started from Paul Ottaway's definition of the difference from a short sum (to a normal long sum): The game ends when a player chooses a component in which they have no legal move. This doesn't make a difference in Normal play (because players don't want to choose one of those games) but it's important for Misere. In misere, this is equivalent to: The game ends when there is a component in which the current player has no legal move.
Now, instead of starting from zero as the terminal position, they start with two games that have no options: Infinity (Inf) and negative Infinity (-Inf). Inf is the game with no options for Right, and -Inf has no moves for Left. These are the only games born on day 0. Then the day 1 games are:
- Inf* = {Inf | Inf}
- +/- Inf = {Inf | -Inf} (like a switch)
- 0 = {-Inf | Inf}
- -Inf* = {-Inf | -Inf}
Ugh! Wish I could have been there. Sounds like there were lots of interesting things discussed this year. Hopefully I'll be able to catch up with everyone in Lisbon.
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