COMPUTATION OF P(12)
THE NUMBER OF POSETS WITH 12 ELEMENTS : 1.104.891.746

C. Chaunier and N. Lygeros

For the history of this subject you can see records in combinatorics and number theory.
For the precise table of the computation of the number of posets with 13 or 14 elements see P(13) or P(14).

REFERENCES

  • Calculs exhaustifs sur les posets d'au plus 7 �l�ments.
     SINGULARITE, vol.2 n4 p.10-24, 1991. (N.Lygeros)
  • Petits posets : d�nombrement, repr�sentabilit� par cercles et compenseurs.
     C.R.Acad.Sci.Paris, t.313, s.I, p.417-420, 1991. (R.Fra�ss�, N.Lygeros)
  • Progr�s dans l'�num�ration des posets
    C.R.Acad.Sci.Paris, t.314, s.I, p.691-694, 1992. (C.Chaunier, N.Lygeros)

    RelationsP(12,r)
    r=01
    r=11
    r=23
    r=37
    r=419
    r=547
    r=6133
    r=7352
    r=8997
    r=92753
    r=107558
    r=1119801
    r=1249795
    r=13117875
    r=14263019
    r=15550013
    r=161080422
    r=171993865
    r=183469819
    r=195707944
    r=208909624
    r=2113234277
    r=2218766663
    r=2325468042
    r=2433157695
    r=2541495336
    r=2650008606
    r=2758130096
    r=2865270723
    r=2970888253
    r=3074562234
    r=3176042383
    r=3275275671
    r=3372402491
    r=3467726046
    r=3561666534
    r=3654699028
    r=3747302979
    r=3839908316
    r=3932869931
    r=4026443898
    r=4120792175
    r=4215984309
    r=4312020498
    r=448844848
    r=456370240
    r=464491015
    r=473100063
    r=482094942
    r=491386092
    r=50897535
    r=51568627
    r=52352196
    r=53213115
    r=54125818
    r=5572382
    r=5640515
    r=5721985
    r=5811545
    r=595808
    r=602779
    r=611249
    r=62509
    r=63184
    r=6455
    r=6511
    r=661

    These results confirm R. Fra�ss�'s conjecture on unimodality.