UP
- For “Up” as a direction on the board see Up and down.
In Combinatorial Game Theory, UP is the name of an infinitesimal, also written ↑. UP is defined as
- ``uarr = { 0 | ast }``
Left (Black) can play to ``0``, while Right (White) can play to ``ast`` (STAR). UP is positive, favoring Left, who gets the last play, no matter who goes first. The opposite of UP is DOWN, also written ↓.
Some plays with a miai value of 1 chill to UP. (See Chilled Go). Here is an example:
This position chills to 2↑ (shorthand for 2 + ↑). Black can get the last play locally no matter who plays first.
See also
- Go infinitesimals — On the significance of infinitesimals in go
- Corridor infinitesimals — On the (infinitesimal) chilled values of corridors
- Playing infinitesimals — On playing positions of infinitesimal value in the correct order
Notes and discussion
Robert Pauli:
How about this position for exactly UP?
Reply:
OC, it is a chilled up.
![[Diagram]](../../diagrams/43/88b3fdd02b849b49818e153dd2e17910.png)
![[Diagram]](../../diagrams/45/577fc96c4fe974e8ecd46e074b49ba72.png)
2024 the Authors,
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