External and Internal Ko
Quite like it is essential to distinguish neutral region on the outside from territory on the inside, it is important to distinguish external ko from internal ko. This is especially relevant for Ing ko rules or the supplementary ko rule of the World Mind Sports Games 2008 Rules.
The following definition is taken from a paper of Robert Jasiek.
The locale of a ko is the set of its and its adjacent intersections.
For a ko, a closed killer is a closed player who moving first can virtual-force uncapturable life of his on the ko.
For a ko, a strong killer is a closed player who moving first can virtual-force uncapturable life of his on the locale.
A ko is external if a closed killer exists that is not a strong killer.
A ko is internal unless it is external.
Page contents: RobertJasiek.