### A trade deficit

But, what about the negative numbers?
Can we talk about **minus** the set {Ulla, Henriette, Vignette}?

that is, is there a "set" *X* such that the union of *X* and {Ulla,
Henriette, Vignette} is the empty set (don't fool yourself into believing that *X*="the wolf": the union of UHV and the wolf is a (nonempty) wolf).

Out in space

Bjørn Ian Dundas
2017-07-21 14:40:56 UTC