Constrained local necessary conditions
Theorem
Assume thatφkk= 0 , 1 , 2 ,.. .,p are di§erentiable and assume thatφ 0
has a local minimum at x 0 on the set
X$fxjφk(x)= 0 ,k= 1 ,.. .,pg.
Then there are multipliers
l=(λ 0 ,λ 1 ,.. .,λp) 2 Rp+^1
such that p
∑
k= 0
λkφ^0 k(x 0 )= 0.
Ifφ^0 k(x 0 ),k= 1 ,.. .,p are linearly independent thenλ 0 = 1 is possible.