Three players place points on a gold bar of length 1, one after another. Each gets the portion closest to their point (a 1D Voronoi split). Everyone plays optimally.
What can Player 1 guarantee?
Start from the end.
Player 3 (last mover) will always place themselves to steal the largest available gap. They react, not commit.
Player 2 knows this. So instead of chasing the biggest immediate slice, they position to limit how much Player 3 can steal.
Now Player 1 has to think two steps ahead: “Where do I place so that even after both optimal responses, I still get the most?”
Key insight:
If Player 1 does NOT start in the middle, they lose control.
* Suppose Player 1 shifts left.
* Player 2 moves toward the larger right side.
* Player 3 then jumps to the far right endpoint.
* Result: Player 1 gets squeezed into a smaller region.
This always punishes imbalance.
But if Player 1 starts exactly at 1/2:
* Player 2’s best move is symmetric (slightly left or right of center)
* Player 3 ta...
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