Robertson Condition
For the Helmholtz Differential Equation to be Separable in a coordinate system, the Scale Factors 
in the Laplacian
 | (1) |
and 
defined by | (2) |
 | (3) |
References
Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part 1. New York: McGraw-Hill, p. 510, 1953.
- Lagrange Resolvent
- Lagrange's Continued Fraction Theorem
- Lagrange's Equation
- Lagrange's Four-Square Theorem
- Lagrange's Group Theorem
- Lagrange's Identity
- Lagrange's Interpolating Fundamental Polynomial
- Lagrange's Lemma
- Lagrange Spectrum
- Lagrangian Coefficient
- Lagrangian Derivative
- Laguerre Differential Equation
- Laguerre-Gauss Quadrature
- Laguerre Polynomial
- Laguerre Quadrature
- Laguerre's Method
- Laguerre's Repeated Fraction
- Laisant's Recurrence Formula
- Lakshmi Star
- Lal's Constant
- Laman's Theorem
- Lambda Calculus
- Lambda Function
- Lambda Group
- Lambda Hypergeometric Function