IsBasis - Maple Help
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Groebner

  

IsBasis

  

test for a Groebner basis

 

Calling Sequence

Parameters

Description

Examples

Compatibility

Calling Sequence

IsBasis(G, T)

IsBasis(G, T, characteristic=p)

Parameters

G

-

set or list of polynomials

T

-

MonomialOrder or ShortMonomialOrder

p

-

(optional) characteristic

Description

• 

IsBasis(G, T) outputs true if G is a Groebner basis for the ideal I generated by G with respect to the monomial order T and false otherwise.

• 

The test applies Buchberger's S-polynomial criterion which states that G is a Groebner basis for I if and only if the S-polynomial of each pair of polynomials in G when divided by G has 0 remainder.  Note, this test can take longer than the time it takes to compute the Groebner basis.

• 

The argument T is a monomial order.  For a list of available monomial orders, see the Monomial Orders help page.

• 

An optional argument characteristic=p can be used to specify the ring characteristic. The default value is zero.

Examples

> 

with⁡Groebner:

> 

G≔x2+1,y2+x+1

G≔x2+1,y2+x+1

(1)

Our example shows that whether G is not a Groebner basis or not depends on the monomial ordering.

> 

IsBasis⁡G,grlex⁡x,y

true

(2)
> 

IsBasis⁡G,plex⁡x,y

false

(3)
> 

s≔SPolynomial⁡G1,G2,plex⁡x,y

s≔−x⁢y2−x+1

(4)
> 

NormalForm⁡s,G,plex⁡x,y

y4+2⁢y2+2

(5)

Now we compute a (reduced) Groebner basis for the ideal generated by G in the lexicographical monomial ordering with y<x.

> 

H≔Basis⁡G&comma;plex⁡x&comma;y

H≔y4+2⁢y2+2&comma;y2+x+1

(6)
> 

IsBasis⁡H&comma;plex⁡x&comma;y

true

(7)

Compatibility

• 

The Groebner[IsBasis] command was introduced in Maple 16.

• 

For more information on Maple 16 changes, see Updates in Maple 16.

See Also

Basis

Monomial Orders

MonomialOrder

NormalForm

SPolynomial