398 Chapter^6
and
Ux =A [Vy Wyl' Vx = A [ Wy Uy] , Wx =A [Uy Vy l
Vz Wz Wz Uz Uz Vz
Uy=,;\ [ Vz Wz], Vy = ,;\ [ Wz Uz] , Wy = ,\ [ Uz Vz l
Vx Wx Wx Ux Ux Vx
Uz =A [ Vx Wxl' Vz =A [ Wx Ux] , Wz =A [ Ux Vx l
Vy Wy Wy Uy Uy Vy
where .A = 1/VE. The last nine equations are the generalized Cauchy-
Riemann equations in ~^3 •
By using the equations in the first column above, one obtains
(VEux)x + (VEuy)y + (VEuz)z = 0
which is the generalization of the Laplace equation. The same equation is
also satisfied by v and by w.
The present author [51] has used the same approach to extend these
results to ~n (n 2:: 2). We consider in ~n a regular arc 1: [a, b] ~ ~n
defined by
a::::; u::::; b, i = 1, ... ,n
where the summation convention is used and { ei, ... , en} is the sta.ndard
orthonormal basis in ~n.
Let f = (!^1 , ... , Jn) be a vector function defined in some region n c ~n
containing 1*, with components Ji of class C(^1 )(U), and let
f('y) = r: f(x) = yi(u)ei,
be the image of I under f, so that
y i( u ) = Ji( x ,^1 ... ,x n)
for each i. Since
=
du oxi du
it follows that
I
()Ji I ..
J = Jr(x) = 8xi = la'J I =f. 0
at x = p is a sufficient condition for r to be also regular at the correspond-
ing point f(p ). In what follows it is assumed that the condition Jr(P) =f. 0
is satisfied.