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# isCDG -- whether a permutation is CDG.

- Usage:
    `isCDG w`
- Inputs:
  - w, a permutation,
- Outputs:
  - a Boolean value,

## Description

A permutation $p$ is Conca-De Negri-Gorla (CDG) if it avoids all of the following patterns: $13254$, $21543$, $214635$, $215364$, $215634$, $241635$, $315264$, and $4261735$.

    i1 : p = permutation {3,1,2,5,4}

    o1 = Permutation{3, 1, 2, 5, 4}

    o1 : Permutation

    i2 : isCDG p

    o2 = true

## Acknowledgement

This method was ported over from the MatrixSchubert package.

## See also

- avoidsPattern -- whether a permutation avoids a pattern
- avoidsPatterns -- whether a permutation simultaneously avoids a list of patterns
- isCartwrightSturmfels -- whether a permutation is Cartwright-Sturmfels
- isSeparable -- whether a permutation is separable.
- isVexillary -- whether a permutation is vexillary

## Ways to use isCDG:

- `isCDG(Permutation)`

## For the programmer

The object isCDG is a method function.

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/Permutations/Documentation/patternAvoidanceDocs.m2:124:0.