A 2→1 dimensional function which passes continuity tests along the x axis but is not actually continuous in the general sense: `x²y / (x² + y²)`

.

@isomorphisms Let ƒ:ℝ→ℝⁿ,g:ℝ→ℝ. Then the composition ƒg:ℝ→ℝ is defined for each x in the domain of g yfrog.com/oe71234741j

— rjp (@ryanprociuk) September 6, 2012