Macaulay2 » Documentation
Packages » CoincidentRootLoci :: isMember(RingElement,CoincidentRootLocus)
next | previous | forward | backward | up | index | toc

# isMember(RingElement,CoincidentRootLocus) -- test membership in a coincident root locus

- Function: isMember
- Usage:
    `member(F,X)`
- Inputs:
  - F, a ring element, a binary form
  - X, a coincident root locus
- Outputs:
  - a Boolean value, whether $F$ belongs to $X$

## Description

    i1 : R := QQ[x,y];

    i2 : F = x^7-3*x^6*y+5*x^5*y^2-7*x^4*y^3+7*x^3*y^4-5*x^2*y^5+3*x*y^6-y^7

          7     6      5 2     4 3     3 4     2 5       6    7
    o2 = x  - 3x y + 5x y  - 7x y  + 7x y  - 5x y  + 3x*y  - y

    o2 : QQ[x..y]

    i3 : member(F,coincidentRootLocus {3,2,2})

    o3 = true

    i4 : member(F,coincidentRootLocus {5,2})

    o4 = false

## See also

- random(CoincidentRootLocus) -- get a random element

## Ways to use this method:

- isMember(RingElement,CoincidentRootLocus) -- test membership in a coincident root locus

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/CoincidentRootLoci/documentation.m2:153:0.