Min

Forward the minimum in-bucket value.

Selects rather than accumulates, so weight does not enter: a minimum has no multiplicity to scale. The consequence is worth stating, because it is the one place resampling does not do what a negative weight asks. A downdate small enough to leave the bucket's weight positive is accepted and reduces that weight, but the value it meant to retract still competes for the extremum, since there is no arithmetic that removes a value from a minimum. Reach for Mean or Sum where retraction has to be exact.