CASA Function: singLocus

Compute singularities of an algebraic set.

Calling Sequence:

• B := singLocus(A)
• B := singLocus(A,vars)

Parameters:

A : algset

• An algebraic set.

vars : list(name)

• A list of CASA variables in which the resulting algebraic set will be specified.

Result:

B : algset("impl")

• The algebraic set of singularities of the given algebraic set.

Description:

• The function computes the algebraic set of all singularities of a given algebraic set
• This can only be done for algebraic sets not given by places. For algebraic sets in implicit form the partial derivatives with respect to the variables in variableList(A) are computed. Algebraic sets in parametric or in projected form are first converted to implicit form.
• A second parameter can be given to specify the variables that should be used for the resulting algebraic set.
• The function returns an algebraic set in implicit form in affine space.

Examples:

> A := mkImplAlgSet([x^2+x^3-y^2],[x,y]);

> L := singLocus(A);

> tsolve(L);

See Also: