Editing Kolmogorov space (section)

===Spaces that are not T<sub>0</sub>===

*A set with more than one element, with the [[trivial topology]]. No points are distinguishable.
*The set '''R'''<sup>2</sup> where the open sets are the Cartesian product of an open set in '''R''' and '''R''' itself, i.e., the [[product topology]] of '''R''' with the usual topology and '''R''' with the trivial topology; points (''a'',''b'') and (''a'',''c'') are not distinguishable.
*The space of all [[measurable function]]s ''f'' from the [[real line]] '''R''' to the [[complex plane]] '''C''' such that the [[Lebesgue integral]] <math>\left(\int_{\mathbb{R}} |f(x)|^2 \,dx\right)^{\frac{1}{2}} < \infty </math>. Two functions which are equal [[almost everywhere]] are indistinguishable. See also below.