Do color terms form a topos?

One way to describe fuzzy sets is to assign each one not only a membership function but also an equivalence relation which gives the degree of similarity of any two member elements to each other. If this is done, it can be shown that fuzzy sets form a topos. Assuming fuzzy sets of this kind, this paper applies some of the resultant properties to the analysis of color terms in human language and cognition. Fuzzy sets have been used to model the basic color terms of human language for some time, but the application has been, for the most part, superficial and has not contributed materially to deep understanding of the issues. This paper carries the work a bit further by suggesting that not only fuzzy sets but also their systematic (topos-theoretic) aspects should be considered when modeling color in human cognition.