define a constant, scalar, or form - Maple Help

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difforms[defform] - define a constant, scalar, or form

Calling Sequence

defform(n1 = e1, n2 = e2, . . . )

Parameters

n1, n2, ...

-

names or calls to difforms[d]

e1, e2, ...

-

Maple expressions

Description

• 

The function defform is used to define the basic variables used in a computation, or to define the exterior derivative of an expression.

• 

The function defform clears the remember tables of all functions in the forms package, as changing the definition of a form can make the remembered results invalid. However, definitions made through defform are not cleared; they are remembered permanently.

• 

The function defform takes an arbitrary number of equations, where each equation is name = expr. There are certain expressions - const, scalar, form, odd, even, -1, and 0 that have special meanings.  Except for these, name = expr means name is a form and wdegree(name) = expr.

• 

The expression const or -1 means type(name,const) is true.  The name even or odd means type(name,const) is true, but also that parity(name) is 0 or 1, as appropriate.  The names even and odd are useful for specifying a form with even or odd, but otherwise unknown wdegree.

• 

The expression scalar or 0 means type(name,scalar) is true.  The name form means that type(name,form) is true, but does not give a value to wdegree(name).

• 

The function defform can be used to define the exterior derivative of an expression, and these derivatives are remembered permanently.

• 

The wdegree of an indexed name is by default the wdegree of the non-indexed name. Values of wdegree for a particular index can be explicitly stated.

• 

The command with(difforms,defform) allows the use of the abbreviated form of this command.

Examples

withdifforms:

defforma=const,b=scalar,e=nonhmg,j=3,f=odd,l=f3,dl=e,t=2,t3=4

typea,const

true

(1)

typeb,scalar

true

(2)

typee,form,wdegreee

true,nonhmg

(3)

typej,form,wdegreej

true,3

(4)

typef,const,parityf

true,1

(5)

dl

e

(6)

wdegreet

2

(7)

wdegreet1

2

(8)

wdegreet3

4

(9)

wdegreeu3=wdegreeu

wdegreeu=wdegreeu

(10)

See Also

type/const, type/scalar, wdegree


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