pass-alive

    Keywords: Life & Death, Go term

A group is pass-alive if it keeps its alive status even if the defender continues to pass whenever the attacker makes a play.

Example

[Diagram]
A pass-alive group  

No matter what White tries against this group, it can not be captured.

[Diagram]
This group is not pass-alive  

This group, although it is normally considered alive, is not pass-alive: If black keeps passing, the group can be captured by White - by playing at a, b, c and d for example.


Notes

RobertJasiek: For the Japanese 2003 Rules it has been necessary to reinvent this concept. There the definition is:

Consider a string of a player in a position. The string is pass-alive if for the hypothetical-strategy of the player that consists of only passes the opponent does not have any hypothetical-sequence that starts from the position, with the opponent, and has a capture of the string.

Note: This definition presumes some other definitions for the terms used therein.

Note: This term can be used as an alternative for the ambiguous unconditional life.

See also


pass-alive last edited by 213.73.114.174 on March 25, 2012 - 18:32
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