1.AdjectiveOf a differentiable function
f
:
R
n
→
R
{\displaystyle f:\mathbb {R} ^{n}\to \mathbb {R} }
, being such that there exists a vector valued function g such that
f
(
x
)
−
f
(
u
)
≥
g
(
x
,
u
)
⋅
∇
f
(
u
)
,
{\displaystyle f(x)-f(u)\geq g(x,u)\cdot \nabla f(u),\,}
for all x and u.