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Macdonald's Plane Partition Conjecture


Macdonald's plane partition conjecture proposes a formula for the number of cyclically symmetric plane partitions (CSPPs) of a given integer whose Ferrers diagrams fit inside an n×n×n box. Macdonald gave a product representation for the power series whose coefficients q^n were the number of such partitions of n.

Let D(pi) be the set of all integer points (i,j,k) in the first octant such that a plane partition pi=(a_(ij)) is defined and 1<=k<=a_(ij). Then pi is said to be cyclically symmetric if D(pi) is invariant under the mapping (i,j,k)->(j,k,i). Let M(m,n) be the number of cyclically symmetric partitions of n such that none of i,j,a_(ij) exceed m. Let B_m be the box containing all integer points (i,j,k) such that 1<=i,j,k<=m, then M(m,n) is the number of cyclically symmetric plane partitions of n such that D(pi) subset= B_m. Now, let C_m be the set of all the orbits in B_m. Finally, for each point p=(i,j,k) in B_m, let its height

 ht(p)=i+j+k-2
(1)

and for each xi in C_m, let |xi| be the number of points in xi (either 1 or 3) and write

 ht(xi)=sum_(p in xi)ht(p).
(2)

Then Macdonald conjectured that

S_m=sum_(n>=0)M(m,n)q^n
(3)
=product_(xi in C_m)(1-q^(|xi|+ht(xi)))/(1-q^(ht(xi)))
(4)
=product_(i=1)^(m)[(1-q^(3i-1))/(1-q^(3i-2))product_(j=i)^(m)(1-q^(3(m+i+j-1)))/(1-q^(3(2i+j-1)))],
(5)

(Mills et al. 1982, Macdonald 1995), where the latter form is due to Andrews (1979).

The first few polynomials are

S_0=1
(6)
S_1=1+q
(7)
S_2=1+q+q^4+q^7+q^8
(8)
S_3=1+q+q^4+2q^7+q^8+q^(10)+q^(11)+2q^(13)+2q^(14)+q^(16)+q^(17)+q^(19)+2q^(20)+q^(23)+q^(26)+q^(27),
(9)

which converge to the polynomial with coefficients 1, 1, 0, 0, 1, 0, 0, 2, 1, 0, 2, 1, 0, 4, 3, 0, 5, 4, 0, 8, 8, ... (OEIS A096419).

Andrews (1979) proved the q=1 case, giving the total number of CSPPs fitting inside an n×n×n box. The general case was proved by Mills et al. (1982).


See also

Cyclically Symmetric Plane Partition, Dyson's Conjecture, Plane Partition, Root System, Zeilberger-Bressoud Theorem

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References

Andrews, G. E. "Plane Partitions (III): The Weak Macdonald Conjecture." Invent. Math. 53, 193-225, 1979.Andrews, G. E. "Macdonald's Conjecture and Descending Plane Partitions." In Combinatorics, Representation Theory and Statistical Methods in Groups (Ed. T. V. Narayana, R. M. Mathsen, and J. G. Williams). New York: Dekker, pp. 91-106, 1980.Bressoud, D. Proofs and Confirmations: The Story of the Alternating Sign Matrix Conjecture. Cambridge, England: Cambridge University Press, 1999.Bressoud, D. and Propp, J. "How the Alternating Sign Matrix Conjecture was Solved." Not. Amer. Math. Soc. 46, 637-646.Macdonald, I. G. "Some conjectures for Root Systems." SIAM J. Math. Anal. 13, 988-1007, 1982.Macdonald, I. G. Symmetric Functions and Hall Polynomials, 2nd ed. Oxford, England: Oxford University Press, 1995.Mills, W. H.; Robbins, D. P.; and Rumsey, H. Jr. "Proof of the Macdonald Conjecture." Invent. Math. 66, 73-87, 1982.Morris, W. G. Constant Term Identities for Finite and Affine Root Systems: Conjectures and Theorems. Ph.D. thesis. Madison, WI: University of Wisconsin, 1982.Sloane, N. J. A. Sequence A096419 in "The On-Line Encyclopedia of Integer Sequences."

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Macdonald's Plane Partition Conjecture

Cite this as:

Weisstein, Eric W. "Macdonald's Plane Partition Conjecture." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/MacdonaldsPlanePartitionConjecture.html

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