Approximate jump point
= Approximate jump point
{title2=$u^+,u^-,\nu_u$}
A scalar function in the <BV space> has an approximate jump at a point when its mean on each of two half-balls approaches a different finite value. The half-balls are determined by a unit normal $\nu_u$. Reversing the normal exchanges the two <BV traces on a hypersurface>. Their collection is the <jump set of a BV function>.