Digi Area Group - Math Tools for Professionals
   Maple and Mathematica packages - math tools for professionals

atlas™ - modern differential geometry for Maple™

> Features List & Examples
> Template Worksheets
> Screenshots
> Documentation & Downloads
> License & Pricing
> Buy Online

 
 
 
 
Google

Features List & Examples  |  Introduction  |  Dimension  |  Indexing  |  Forms  |  Metric  |  atlasWizard - Maplet™

atlas[Forms] - declaration of p-forms

Calling Sequence:

     Forms(F1=n, F2=k, ..., Fi=p)

Parameters:

      Fi=p  - equations where Fi - form identifier and p is a variable or an integer - the form's degree.

Description:

  • In the atlas  package any identifier is treated as 0-form  i.e. as non-constant scalar  (if it not declared as constant, p-form, tensor etc. (see atlas[types] )).
  • The Forms  procedure declares p-forms. One can declare indexed p-forms e.g. e[j]  is treated as a set of p-forms e[1], e[2], `` .. e[j], `` .. ``

Examples:
restart:
with(atlas):

Declare some forms:
Forms(e[i]=1,phi=1,z=1,omega=2,alpha=q,beta=p);

{z, phi, e[i], omega, alpha, beta}

Varify that e[1] is 1-form using kind procedure (see atlas[kind] ):
kind(e[1]);

[0, 1]

Using exterior product operator (see atlas[`&^`] ):
'omega&^beta'=omega&^beta;

`&^`(omega,beta) = (-1)^(2*p)*`&^`(beta,omega)

'beta&^alpha'=beta&^alpha;

`&^`(beta,alpha) = (-1)^(p*q)*`&^`(alpha,beta)

Some more examples:
'e[j]&^e[i]'=e[j]&^e[i];

`&^`(e[j],e[i]) = -`&^`(e[i],e[j])

'kind(d(beta))'=kind(d(beta));

kind(d(beta)) = [0, 1+p]

And more:

p - was not declared as a constant!
'd(omega&^beta)'=d(omega&^beta);

d(`&^`(omega,beta)) = 2*(-1)^(2*p)*ln(2*p)*(-1)^(2+3*p)*`&^`(omega,beta,d(p))+(-1)^(2*p)*((-1)^(2+2*p)*`&^`(omega,d(beta))+(-1)^p*`&^`(beta,d(omega)))
d(`&^`(omega,beta)) = 2*(-1)^(2*p)*ln(2*p)*(-1)^(2+3*p)*`&^`(omega,beta,d(p))+(-1)^(2*p)*((-1)^(2+2*p)*`&^`(omega,d(beta))+(-1)^p*`&^`(beta,d(omega)))

'd(beta&^omega)'=d(beta&^omega);

d(`&^`(beta,omega)) = (-1)^(2+2*p)*`&^`(omega,d(beta))+(-1)^p*`&^`(beta,d(omega))

Declare p as a constant:
Constants(p);

{_Z, Pi, I, p, -I, Catalan}

Thus:
'd(omega&^beta)'=d(omega&^beta);

d(`&^`(omega,beta)) = (-1)^(2*p)*((-1)^(2+2*p)*`&^`(omega,d(beta))+(-1)^p*`&^`(beta,d(omega)))

Let's see "who is who"
Who([alpha,beta,omega,e[j],x,y,z,p]);


alpha: q - form

beta: p - form

omega: 2 - form

e[j]: 1 - form

x: 0 - form

y: 0 - form

z: 1 - form

p: constant


Who();

PIECEWISE([{}, Domains],[{}, Mappings],[{z, phi, e[i], omega, alpha, beta}, Tensors],[{z, phi, e[i], omega, alpha, beta}, Forms],[{_Z, Pi, I, p, -I, Catalan}, Constants],[{}, Functions])

See Also:

atlas , atlas[Constants] , atlas[Functions] , atlas[Vectors] , atlas[Tensors] , atlas[d] , atlas[`&^`] , atlas[Who] .