
BASIC NOTATION AND REMARKS
Latin Characters
curl u curl of a vector u, sometimes also denoted by rot u
div u divergence of a vector u; div u =
∂u
1
∂x
+
∂u
2
∂y
in the two-dimensional case
u = (u
1
, u
2
)
E fundamental solution of the Cauchy problem
E
e
fundamental solution corresponding to an operator (or fundamental so-
lution of an equation)
grad a gradient of a scalar a, also denoted by ∇a, where ∇ is the nabla vector
differential operator
Im[A] imaginary part of a complex number A
G Green function
R
n
n-dimensional Euclidean space, R
n
= {−∞ < x
k
< ∞; k = 1, . . . , n}
Re[A] real part of a complex number A
r, ϕ, z cylindrical coordinates, r =
p
x
2
+ y
2
with x = r cos ϕ