OFFSET
1,2
COMMENTS
Heat-Charge Toggle is an impartial two-player game on a finite simple graph, where each vertex is assigned a weight of -1, 0, or 1.
A Heat-Charge Toggle move consists of selecting a vertex of weight 1 and switching its weight to 0, as well as switching the sign of each of its neighbors: changing 1 to -1, -1 to 1, and keeping 0 at 0.
We additionally only allow moves that strictly decrease the sum of all weights.
The two vertices of degree one have initial weights of -1, while vertices of degree two have an initial weight of 1.
REFERENCES
E. R. Berlekamp, J. H. Conway, and R. K. Guy, Winning Ways for Your Mathematical Plays, Vol. 1, CRC Press, 2001.
LINKS
Nathan Hurtig, C++ program to compute values
EXAMPLE
For n = 4, the Sprague-Grundy value for a 6-vertex path is 2.
Note that n = 4 is even and 2 is odious (see A000069).
CROSSREFS
KEYWORD
nonn
AUTHOR
Jean-Pierre Appel, Patrick G. Cesarz, Djeneba Diop, Eugene Fiorini, Nathan Hurtig, Andrew Woldar, Jul 26 2023
STATUS
approved