I remember studying this problem in the context of anonymity a few years back, defining immeasurability as the property whereby an adversary cannot distinguish

I remember studying this problem in the context of anonymity a few years back, defining immeasurability as the property whereby an adversary cannot distinguish between different node counts, for example. The tank problem is related to mark recapture techniques for animal population size estimation. Shameless plug, http://www.cs.technion.ac.il/users/wwwb/cgi-bin/tr-get.cgi/2011/MSC/MSC-2011-06.pdf http://www.cs.technion.ac.il/users/wwwb/cgi-bin/tr-get.cgi/2...