oh. searching a space of independently sorted dimensions for a single target value has worst-case complexity that's entirely independent of the number of dimensions.

that is, assuming every observation gives you the direction towards target along every dimension, just do binary search independently for all of them. the worst-case complexity depends purely on the size of the biggest dimension. prob true wrt avg case too.

…everyone knows this already, say? in my defence, rediscovering>>reading.