You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
Copy file name to clipboardExpand all lines: docs/src/modules.md
+12Lines changed: 12 additions & 0 deletions
Display the source diff
Display the rich diff
Original file line number
Diff line number
Diff line change
@@ -433,6 +433,18 @@ Return the numbers of partitions of an ``n``-set into ``m`` nonempty subsets.
433
433
434
434
## Set partitions of m-type
435
435
436
+
For example consider the case n = 4. There are five integer partitions of 4:
437
+
438
+
* P = [[4], [3, 1], [2, 2], [2, 1, 1], [1, 1, 1, 1]]. The shapes are m times the parts of the integer partitions: S(m) = [[4m], [3m, m], [2m, 2m], [2m, m, m], [m, m, m, m]].
439
+
440
+
* In the case m = 1 we look at set partitions of {1, 2, 3, 4} with sizes in [[4], [3, 1], [2, 2], [2, 1, 1], [1, 1, 1, 1]] which gives rise to [1, 4, 3, 6, 1] with sum 15.
441
+
442
+
* In the case m = 2 we look at set partitions of {1, 2, .., 8} with sizes in [[8], [6, 2], [4, 4], [4, 2, 2], [2, 2, 2, 2]] which gives rise to [1, 28, 35, 210, 105] with sum 379.
443
+
444
+
* In the case m = 0 we look at set partitions of {} with sizes in [[0], [0, 0], [0, 0], [0, 0, 0], [0, 0, 0, 0]] which gives rise to [1, 1, 1, 1, 1] with sum 5 (because the only partition of the empty set is the set that contains the empty set, thus from the definition T(0,4) = Sum_{S(0)} card({0}) = A000041(4) = 5).
445
+
446
+
* If n runs through 0, 1, 2,... then the result is an irregular triangle in which the n-th row lists multinomials for partitions of [m*n] which have only parts which are multiples of m. These are the triangles A080575 (m = 1), A257490 (m = 2), A327003 (m = 3), A327004 (m = 4). In the case m = 0 the triangle is A000012 subdivided into rows of length A000041. See the references below how this case integrates into the full picture.
447
+
436
448
| type | m = 0 | m = 1 | m = 2 | m = 3 | m = 4 |
437
449
|-------|-------|-------|-------|-------|-------|
438
450
| by shape |[A000012](https://oeis.org/A000012)|[A036040](https://oeis.org/A036040)|[A257490](https://oeis.org/A257490)|[A327003](https://oeis.org/A327003)|[A327004](https://oeis.org/A327004)|
For example consider the case n = 4. There are five integer partitions of 4:
7900
+
7901
+
* P = [[4], [3, 1], [2, 2], [2, 1, 1], [1, 1, 1, 1]]. The shapes are m times the parts of the integer partitions: S(m) = [[4m], [3m, m], [2m, 2m], [2m, m, m], [m, m, m, m]].
7902
+
7903
+
* In the case m = 1 we look at set partitions of {1, 2, 3, 4} with sizes in [[4], [3, 1], [2, 2], [2, 1, 1], [1, 1, 1, 1]] which gives rise to [1, 4, 3, 6, 1] with sum 15.
7904
+
7905
+
* In the case m = 2 we look at set partitions of {1, 2, .., 8} with sizes in [[8], [6, 2], [4, 4], [4, 2, 2], [2, 2, 2, 2]] which gives rise to [1, 28, 35, 210, 105] with sum 379.
7906
+
7907
+
* In the case m = 0 we look at set partitions of {} with sizes in [[0], [0, 0], [0, 0], [0, 0, 0], [0, 0, 0, 0]] which gives rise to [1, 1, 1, 1, 1] with sum 5 (because the only partition of the empty set is the set that contains the empty set, thus from the definition T(0,4) = Sum_{S(0)} card({0}) = A000041(4) = 5).
7908
+
7909
+
* If n runs through 0, 1, 2,... then the result is an irregular triangle in which the n-th row lists multinomials for partitions of [m*n] which have only parts which are multiples of m. These are the triangles A080575 (m = 1), A257490 (m = 2), A327003 (m = 3), A327004 (m = 4). In the case m = 0 the triangle is A000012 subdivided into rows of length A000041. See the references below how this case integrates into the full picture.
@@ -8288,79 +8301,135 @@ L005046(len) = [V005046(n) for n in 0:len-1]
8288
8301
8289
8302
Return the number of set partitions of a 2n-set into even blocks which have even length minus the number of partitions into even blocks which have odd length.
0 commit comments