RationalMapImage - Maple Help
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RegularChains[ConstructibleSetTools]

  

RationalMapImage

  

compute the image of a variety or a constructible set under a rational map

 

Calling Sequence

Parameters

Description

Examples

Calling Sequence

RationalMapImage(F, RM, R, S)

RationalMapImage(F, H, RM, R, S)

RationalMapImage(CS, RM, R, S)

Parameters

F

-

list of polynomials

RM

-

a list of rational functions in R

R

-

a polynomial ring (source)

S

-

a polynomial ring (target)

H

-

list of polynomials

CS

-

constructible set

Description

• 

The command RationalMapImage(F, RM, R, S) returns a constructible set cs which is the image of the variety V⁡F under the rational map RM.

• 

If H is specified, let W be the variety defined by the product of polynomials in H. The command RationalMapImage(F, H, RM, R, S) returns the image of the constructible set V-W under the rational map RM.

• 

The command RationalMapImage(CS, RM, R, S) returns the image of the constructible set CS under the rational map RM.

• 

Both rings R and S should be over the same ground field.

• 

The variable sets of R and S should be disjoint.

• 

The number of polynomials in RM is equal to the number of variables of ring S.

Examples

> 

with⁡RegularChains:

> 

with⁡ConstructibleSetTools:

The following example is related to the tacnode curve.

> 

S≔PolynomialRing⁡t

S≔polynomial_ring

(1)
> 

T≔PolynomialRing⁡x,y

T≔polynomial_ring

(2)
> 

F≔

F≔

(3)
> 

RM≔t3−6⁢t2+9⁢t−22⁢t4−16⁢t3+40⁢t2−32⁢t+9,t2−4⁢t+42⁢t4−16⁢t3+40⁢t2−32⁢t+9

RM≔t3−6⁢t2+9⁢t−22⁢t4−16⁢t3+40⁢t2−32⁢t+9,t2−4⁢t+42⁢t4−16⁢t3+40⁢t2−32⁢t+9

(4)
> 

cs≔RationalMapImage⁡F,RM,S,T

cs≔constructible_set

(5)
> 

Info⁡cs,T

2⁢x4−3⁢y⁢x2+y4−2⁢y3+y2,y,10⁢y+2⁢x2+2⁢y3−y2−y,964⁢y6−480⁢y5−6858⁢y4−4328⁢y3−888⁢y2−72⁢y−2⁢x2−88⁢y8+2104⁢y7−2316⁢y6−943⁢y5+892⁢y4+318⁢y3+32⁢y2+y,x,y−1,1,x,y,1

(6)

See Also

ConstructibleSet

Difference

MakePairwiseDisjoint

Projection

RegularChains