IsTransverse - Maple Help
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RegularChains[AlgebraicGeometryTools]

  

IsTransverse

  

check whether an hypersurface and a space curve meet transversely

 

Calling Sequence

Parameters

Description

Examples

References

Compatibility

Calling Sequence

IsTransverse(rc,f, F, R)

Parameters

R

-

polynomial ring

rc

-

regular chain of R

f

-

a polynomial of R

F

-

list of polynomials of R

Description

• 

The command IsTransverse(rc,f, F, R) returns true if and only if the hypersurface defined by f and the space curve defined by F meet transversely at every point defined by the zero-dimensional regular chain rc.

• 

In other words, this command returns true if and only if the hypersurface defined by f and the tangent cone of the space curve defined by F at p intersect at p, and only at p, in a neighbourhood of p, for every point p defined by the regular chain rc.

• 

It is assumed that rc is a zero-dimensional regular chain.

• 

It is assumed that F generates a one-dimensional ideal and F consists of n-1 polynomials where n is the number of variables in R.

• 

It is assumed that the hypersurface defined by f is non-singular at every point defined by rc.

• 

This command is part of the RegularChains[AlgebraicGeometryTools] package, so it can be used in the form IsTransverse(..) only after executing the command with(RegularChains[AlgebraicGeometryTools]).  However, it can always be accessed through the long form of the command by using RegularChains[AlgebraicGeometryTools][IsTransverse](..).

Examples

> 

with⁡RegularChains:with⁡ChainTools:with⁡AlgebraicGeometryTools:

> 

R≔PolynomialRing⁡x,y,z

R≔polynomial_ring

(1)
> 

F≔x,x−y2−z2,y−z3

F≔x,−y2−z2+x,−z3+y

(2)
> 

dec≔Triangularize⁡F,R

dec≔regular_chain,regular_chain

(3)
> 

Display⁡dec,R

x=0y−z3=0z4+1=0,x=0y=0z=0

(4)
> 

IsTransverse⁡dec1,F3,F1..2,R

true

(5)
> 

IsTransverse⁡dec2,F3,F1..2,R

true

(6)

References

  

Steffen Marcus, Marc Moreno Maza, Paul Vrbik "On Fulton's Algorithm for Computing Intersection Multiplicities." Computer Algebra in Scientific Computing (CASC), Lecture Notes in Computer Science - 7442, (2012): 198-211.

  

Parisa Alvandi, Marc Moreno Maza, Eric Schost, Paul Vrbik "A Standard Basis Free Algorithm for Computing the Tangent Cones of a Space Curve." Computer Algebra in Scientific Computing (CASC), Lecture Notes in Computer Science - 9301, (2015): 45-60.

Compatibility

• 

The RegularChains[AlgebraicGeometryTools][IsTransverse] command was introduced in Maple 2020.

• 

For more information on Maple 2020 changes, see Updates in Maple 2020.

See Also

Display

PolynomialRing

RegularChains

Triangularize