MatrixPermanent
The permanent: the sum over the permutations s of the product of a(i, s(i)).
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St001260via AlternatingSignMatrix✓MatrixPermanent(tableau)The permanent: the sum over the permutations s of the product of a(i, s(i)).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 St001260. Ryser's formula: (-1)^n times the sum over the sets S of columns of (-1)^|S| times the product over the rows of the row's sum over S. The sets are the numbers 0 .. 2^n - 1 read in binary.
Definition
Epsil, as the implementation runs it.
on AlternatingSignMatrix, over _x
0 if Length(_x) < 1 else Apply((cells: list<integer>) => Apply((side: integer) => Sum(Map(Function((-1) ^
(side +
Sum(Map(Function((m -
m %
2 ^
(j - 1)) /
2 ^
(j - 1) %
2, j), Range(1, Length(_x))))) *
Product(Map(
Function(Sum(Map(Function((m -
m %
2 ^
(j - 1)) /
2 ^
(j - 1) %
2 *
cells[(i - 1) *
side +
j], j), Range(1, Length(_x)))), i),
Range(1, Length(_x)),
)), m), Range(0, 2 ^ side -
1))), Length(_x)), Flatten(_x))Examples
Properties #
About
| Examples | 4 |
|---|---|
| Crosswalk | FindStat |