PositiveMatrixInversionNumber
The inversion number less the number of entries equal to -1.
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St000332via AlternatingSignMatrix✓PositiveMatrixInversionNumber(tableau)The inversion number less the number of entries equal to -1.Typed signatures
| Type | Package | Applies |
|---|---|---|
(alternating_sign_matrix) -> number | combinatorics | always |
Details
- Defined over
AlternatingSignMatrixas an expression in_x, evaluated by compute-engine — the definition IS the implementation. - Takes a
AlternatingSignMatrixand nothing else — it reads values against their positions, or walks the orbits, so it needs the bijection. Applying it to a bare list is a type error, not a wrong answer. - FindStat's St000332.
Definition
Epsil, as the implementation runs it.
on AlternatingSignMatrix, over _x
0 if Length(_x) < 1 else Apply((cells: list<integer>) => Apply((side: integer) => Max(Sum(Map(Function(cells[u] *
Max(Sum(Map(
Function(cells[v] if (v -
((v - 1) %
side +
1)) /
side +
1 <
(u -
((u - 1) %
side +
1)) /
side +
1 &&
(v - 1) %
side +
1 >
(u - 1) %
side +
1 else 0, v),
Range(1, side * side),
)), 0), u), Range(1, side * side))), 0) -
Count(Filter(cells, Function(e == -1, e))), Length(_x)), Flatten(_x))Examples
Properties #
About
| Examples | 4 |
|---|---|
| Crosswalk | FindStat |