atlas[`&L`] - Hodge-de Rham Laplacian operator 

Calling Sequence: 

    &L(expr) 

Parameters: 

    expr - any expression. 

Description: 

  • The &L - procedure allows one to calculate the Hodge-de Rham Laplacian on an expression that is p-form.
 

  • The Hodge-de Rham Laplacian is the operator  Delta: Omega[p] -> Psi[p]  where Omega[p] and Psi[p] are p-forms which are defined as follows:
 

  • If omega is  a p-form then, Deltaomega = `+`(d(delta(omega)), delta(d(omega))) where δ is the codifferential (see atlas[`&d`]).
 

Examples: 

> restart:
with(atlas):
 

> Constants(n);
 

{`+`(`-`(I)), I, Pi, _Z, dim, n, Catalan}(2.1)
 

Declare p-forms:  

> Forms(omega=n);
 

{omega}(2.2)
 

Using d- procedure: 

omega - declared as a p-form so we have:
'Delta(omega)'=&L(omega);
 

Delta(omega) = `+`(`*`(`^`(-1, `+`(`*`(`^`(dim, 2)), `*`(dim, `*`(n)), 1)), `*`(d(`&**`(d(`&**`(omega)))))), `*`(`^`(-1, `+`(`*`(`^`(dim, 2)), dim, `*`(dim, `*`(n)), 1)), `*`(`&**`(d(`&**`(d(omega))))...
Delta(omega) = `+`(`*`(`^`(-1, `+`(`*`(`^`(dim, 2)), `*`(dim, `*`(n)), 1)), `*`(d(`&**`(d(`&**`(omega)))))), `*`(`^`(-1, `+`(`*`(`^`(dim, 2)), dim, `*`(dim, `*`(n)), 1)), `*`(`&**`(d(`&**`(d(omega))))...
(2.3)
 

>
 

See Also:  

atlas, atlas[Constants], atlas[Functions], atlas[Forms], atlas[`&^`],  atlas[`&**`], atlas[d], atlas[`&d`].