Abnormal isoperimetric extremal
= Abnormal isoperimetric extremal
{title2=$\delta(\lambda_0J-\lambda_1I)=0$}
If the <first variation> of the constraint vanishes in every allowed direction, the objective coefficient in a general multiplier equation can vanish. One must then allow $\lambda_0F-\lambda_1G$ with coefficients not both zero. Normalizing $\lambda_0$ to one requires the regularity condition used for a <normal isoperimetric extremal>.