Calibration (differential geometry)
= Calibration
{disambiguate=differential geometry}
{title2=$d\varphi=0,\quad\|\varphi\|_*\leq1$}
= Calibration
{synonym}
= Calibration form
{synonym}
A calibration is a closed real <differential form> whose <comass> is at most one. Restricting it to any oriented unit tangent plane therefore gives at most that plane's volume. A <calibrated submanifold> attains equality everywhere, and <calibration implies volume minimization> among homologous competitors.