nabla differential operator |
| Laplacian operator |
~ | isometric to |
, subscript | partial derivative with respect to the following index(es) |
; subscript | covariant derivative with respect to the following index(es) |
1D, 2D, 3D, n D | one-dimensional, two-dimensional, three-dimensional, n -dimensional |
overdot (e.g. r ) | derivative with respect to general parameter t |
prime (e.g. r ) | derivative with respect to natural parameter s |
t | absolute derivative with respect to t |
, i | partial derivative with respect to th and ith variables |
a | determinant of surface covariant metric tensor |
a | surface covariant metric tensor |
a11,a12,a21,a22 | coefficients of surface covariant metric tensor |
a11,a12,a21,a22 | coefficients of surface contravariant metric tensor |
a , a , a | surface metric tensor or its components |
b | determinant of surface covariant curvature tensor |
b | surface covariant curvature tensor |
B | binormal unit vector of space curve |
b11,b12,b21,b22 | coefficients of surface covariant curvature tensor |
b , b , b | surface curvature tensor or its components |
C | curve |
CB , CN , CT | spherical indicatrices of curve C |
Ce , Ci | evolute and involute curves |
Cn | of class n |
c , c , c | tensor of third fundamental form or its components |
d | Darboux vector |
d1 , d2 | unit vectors in Darboux frame |
det | determinant of matrix |
ds | length of infinitesimal element of curve |
dsB,dsN,dsT | length of line element in binormal, normal and tangent directions |
d | area of infinitesimal element of surface |
e,f,g | coefficients of second fundamental form |
E,F,G | coefficients of first fundamental form |
, , V | number of edges, faces and vertices of polyhedron |
Ei , Ej | covariant and contravariant space basis vectors |
E , E | covariant and contravariant surface basis vectors |
Eq./Eqs. | Equation/Equations |
f | function |
g | topological genus of closed surface |
gij , gij | space metric tensor or its components |
H | mean curvature |
IS , IIS , IIIS | first, second and third fundamental forms |
IS , IIS | tensors of first and second fundamental forms |
iff | if and only if |
J | Jacobian of transformation between two coordinate systems |
J | Jacobian matrix |
K | Gaussian curvature |
Kt | surface total curvature |
L | length of curve |
n | normal unit vector to surface |
N | principal normal unit vector to curve |
P | point |
r , R | radius |
Ricci curvature scalar |
r | position vector |
r , r | 1st and 2nd partial derivative of r with respect to subscripted variables |
R1 , R2 | principal radii of curvature |
n | n -dimensional space (usually Euclidean) |
Rij , R ij | Ricci curvature tensor of 1st and 2nd kind for space |
R , R | Ricci curvature tensor of 1st and 2nd kind for surface |
Rijkl | Riemann-Christoffel curvature tensor of 1st kind for space |
R | Riemann-Christoffel curvature tensor of 1st kind for surface |
R ijkl | Riemann-Christoffel curvature tensor of 2nd kind for space |
R | Riemann-Christoffel curvature tensor of 2nd kind for surface |
R | radius of curvature |
R | radius of torsion |
r,, | spherical coordinates of 3D space |
s | natural parameter of curve representing arc length |
S | surface |
ST | tangent surface of space curve |
t | general parameter of curve |
T | function period |
T | tangent unit vector of space curve |
TPS | tangent space of surface S at point P |
tr | trace of matrix |
u | geodesic normal vector |
u1,u2 | surface coordinates |
u | surface coordinate |
u,v | surface coordinates |
xi | space coordinate |
x i | surface basis vector in full tensor notation |
x,y,z | coordinates in 3D space (usually Cartesian) |
[ij,k] | Christoffel symbol of 1st kind for space |
[,] | Christoffel symbol of 1st kind for surface |
kij | Christoffel symbol of 2nd kind for space |
Christoffel symbol of 2nd kind for surface |
ij , ij , ji | covariant, contravariant and mixed Kronecker delta |
ijkl | generalized Kronecker delta |
discriminant of quadratic polynomial |
ijk , ijk | covariant and contravariant relative permutation tensor in 3D space |
ijk , ijk | covariant and contravariant absolute permutation tensor in 3D space |
, | covariant and contravariant relative permutation tensor in 2D space |
, | covariant and contravariant absolute permutation tensor in 2D space |
angle or parameter |
s | sum of interior angles of polygon |
curvature of curve |
, | principal curvatures of surface at a given point |
B , T | curvature of binormal and tangent spherical indicatrices |
g , n | geodesic and normal curvatures |
gu , gv | geodesic curvatures of u and v coordinate curves |
nu , nv | normal curvatures of u and v coordinate curves |
K | curvature vector of curve |
Kg , Kn | geodesic and normal components of curvature vector of curve |
direction parameter of surface |