Nikodym set

In mathematics, a Nikodym set is a subset of the unit square in with complement of Lebesgue measure zero, such that, given any point in the set, there is a straight line that only intersects the set at that point. The existence of a Nikodym set was first proved by Otto Nikodym in 1927. Subsequently, constructions were found of Nikodym sets having continuum many exceptional lines for each point, and Kenneth Falconer found analogues in higher dimensions.

This keyword could refer to multiple things. Here are some suggestions: