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Looking for references for one or more of the following four sets of partition polynomials 1a) through 4a), particularly those which present geometric / topological combinatorial interpretations.

Taking the logarithm of an exponential generating function of moments (or applying OEIS https://oeis.org/[A127671][1] / A263634 ) gives the formal cumulants of classical probability theory whereas taking the shifted reciprocal of the compositional inverse of the ordinary generating function of the moments (or applying A350499, $[N^{(-1)}]$ below, see this MO-Q) gives the formal cumulants of free probability theory. They are interlinked by the analysis below.

For $n = 1,2,3,...$, the infinite set of mutually commuting indeterminates $u_n$, the monomials $M_{n}(e_1,...,e_n) = u_1^{e_1}u_2^{e_2}\cdots u_n^{e_n}$ for the set $\lambda$ of all partitions $(e_1,e_2,...,e_n)$ of $n$ with $n = \sum_{k=1}^n k e_k$, the sum of exponents $Se = \sum_{k=1}^n e_k$, and the multinomial coefficient $\binom{a}{b_1,b_2,...,b_n} = \frac{a!}{b_1!b_2!\cdots b_n!}$,

1a) $[LA]$, the log associahedra,

$$LA_n = \sum_{\lambda} \binom{-n}{Se} \binom{Se}{e_1,e_2,...,e_n} M_{n}(e_1,...,e_n)$$

$$= \sum_{\lambda} (-1)^{Se} \binom{n+Se-1}{Se} \binom{Se}{e_1,e_2,...,e_n} M_{n}(e_1,...,e_n)$$

$$= \sum_{\lambda} (-1)^{Se} \frac{(n+Se-1)!}{(n-1)!} \binom{1}{e_1,e_2,...,e_n} M_{n}(e_1,...,e_n)$$

2a) $[LN]$, the log noncrossing partitions / parking functions (refined Narayana polynomials)

$$LN_n = \sum_{\lambda} \binom{n}{Se} \binom{Se}{e_1,e_2,...,e_n} M_{n}(e_1,...,e_n)$$

$$ = \sum_{\lambda} \frac{n!}{(n-Se)!} \binom{1}{e_1,e_2,...,e_n} M_{n}(e_1,...,e_n)$$

3a) $[ILA] = [LA]^{-1}$, the inverse log associahedra,

$$ILA_n = \sum_{\lambda} (-1)^{Se} \frac{(n+1)^{Se} }{n+1} \binom{1}{e_1,e_2,...,e_n} \binom{1}{2^{e_2},3^{e_3},...,n^{e_n}} M_{n}(e_1,...,e_n)$$

4a) $[ILN] = [LN]^{-1}$. the inverse log noncrossing partitions

$$ILN_n = \sum_{\lambda} (-1)^{n} \frac{(-n+1)^{Se} }{-n+1} \binom{1}{e_1,e_2,...,e_n} \binom{1}{2^{e_2},3^{e_3},...,n^{e_n}} M_{n}(e_1,...,e_n).$$

(Commonly, in references on symmetric functions, something like $ \mu^{\lambda}$ or $\mu_{\lambda}$ denotes the factor $\binom{1}{e_1,e_2,...,e_n} $ and $1/z^{\lambda}$ or $z_{\lambda}^{-1}$ denotes $\mu_{\lambda} \binom{1}{2^{e_2},3^{e_3},...,n^{e_n}}$.)

Examples:

$LA_0 = LN_0= ILA_0 = ILN_0=1$ and

1b) $[LA]$:

$LA_1 = -u_1$

$LA_2 = 3 u_1^2 - 2u_2$

$LA_3 = -10 u_1^3 + 12 u_1 u_2 - 3 u_3$

$LA_4 = 35 u_1^4 - 60 u_1^2 u_2 + 10 u_2^2 + 20 u_1 u_3 - 4 u_4,$

2b) $[LN]$:

$LN_1 = u_1$,

$LN_2 = u_1^2 + 2u_2$,

$LN_3 = u_1^3 + 6 u_2 u_1 + 3 u_3$,

$LN_4 = u_1^4 + 12 u_2 u_1^2 + 12 u_3 u_1 + 6 u_2^2 + 4 u_4.$

3b) $[ILA]$:

$ILA_1 = -u_1$

$ILA_2 = (3u_1^2 - u_2)/2!$

$ILA_3 = (- 16 u_1^3 + 12 u_1 u_2 -2u_3 ) / 3! $

$ILA_4 = (125 u_1^4 - 150 u_2 u_1^2 + 40 u_3 u_1 + 15 u_2^2 - 6 u_4) / 4!,$

4b) $[ILN]$:

$ILN_(u_1) = u_1$,

$ILN_2(u_1,u_2) = (2u_2-2u_1^2)/2!$,

$ILN_3 = (4 u_1^3 - 6 u_2 u_1 + 2u_3)/3!$,

$ILN_4 = (-27 u_1^4 + 54 u_2 u_1^2 - 24 u_3 u_1 - 9 u_2^2 + 6 u_4)/4!.$


Origins and properties:

By inverse set of partition polynomials I mean that substituting the polynomials of the inverse set (on the right) as the indeterminates of the direct set (on the left) gives the substitutional identity; e.g., symbolically, globally,

$$[LN][ILN] =[LN] [LN]^{-1} = [I],$$

and locally, for $n \geq 0$,

$LN_n(u_1,u_2,...,u_n) |_{u_k \to ILN_k(u_1,...,u_k)} = LN_n(ILN_1(u_1),...,ILN_n(u_1,...,u_n)) = u_n$.

Formulating these results in terms of ordinary generating functions (o.g.f.s) / power series reveals numerous identities (and suggests generalizations).

Compositional inversion / series reversion of o.g.f.s $O(x) = x \;( 1 + u_1 x^2 + u_2 x^2 + \cdots)$ can be achieved either via the associahedra partition polynomials $A_n(u_1,...,u_n)$ of A133437 / A111785 or the noncrossing partitions polynomials / parking functions polynomials of A134264 $N_n(b_1,...,b_n)$ with $b_n =R_n(u_1,...,u_n)$ with $[R]$ the set of reciprocal PartPs giving the shifted multiplicative inverse $x/O(x) = 1 + \sum_{n \geq 1} R_n(u_1,...,u_n) x^x$.

With the o.g.f.s $P(t) = 1 + \sum_{n \geq 1} P_n(u_1,...,u_n) t^n$ for $P = A,N,LA,LN,ILA$ or $ILN$

$$LA(t) = \frac{d}{dt} \ln(A(t))$$

and

$$LN(t) = \frac{d}{dt} \ln(N(t)),$$

so $[LA]$ and $[LN]$ can be expressed as the Faber polynomials of A263916, the classic polynomials of symmetric function theory, in particular, the Newton identities, through which the elementary symmetric polynomials / functions and complete homogeneous symmetric polynomials / functions can be expressed in terms of the power sum polynomials.

Equivalently, as sketched in A263634 (cf. also A127671), $LA_n(u_1,...,u_n)$ and $LN_n(u_1,...,u_n)$ are the coefficients of the differential part of the raising operator for the Appell polynomials

$$\bar{A}_n(x) = (\bar{A}_.(u_1,...,u.)+x)^n = \sum_{k=0}^n \binom{n}{k} \bar{A}_k(u_1,...,u_k) x^{n-k} = \sum_{k=0}^n \binom{n}{k} k!A_k(u_1,...,u_k) x^{n-k} $$

and

$$\bar{N}_n(x) = (\bar{N}_.(u_1,...,u.)+x)^n =\sum_{k=0}^n \binom{n}{k} \bar{N}_k(u_1,...,u_k) x^{n-k} = \sum_{k=0}^n \binom{n}{k} k!N_k(u_1,...,u_k) x^{n-k} $$

That is, with $D_x = d/dx$ and

$$R_A = x + LA(D_x)$$

and $$R_N = x + LN(D_x),$$

then

$$\bar{A}_n(x) = R_A \; \bar{A}_{n-1}(x) = R_A^n \; 1$$

and

$$\bar{N}_n(x) = R_N \; \bar{N}_{n-1}(x) = R_N^n \; 1$$

with

$$\bar{A}_n(0) = (\bar{A}.(u_1,...,u.)+0)^n = (\bar{A}.(u_1,...,u.))^n = \bar{A}_n(u_1,...,u_n) = n!A_n(u_1,...,u_n) $$

and

$$\bar{N}_n(0) = n!N_n(u_1,...,u_n).$$

In addition, I can show, several ways, that

$$A(x) = \frac{1}{N^{(-1)}(x)}$$

and

$$N(x) = \frac{1}{A^{(-1)}(x)} $$

where $[N^{(-1)}]=[N]^{-1}$ is the set of ParPs of A350499, for which

$$[N][N^{(-1)}] = [N][N]^{-1}= [I],$$

the identity under substitution, and

$$[A^{(-1)}]= [N]^{-1}[R],$$

is the set of ParPs of A355201.

Then the Appell Sheffer finite operator calculus gives the raising operators for $\bar{N}_n^{(-1)}(x)$ and $\bar{A}_n^{(-1)}(x) $ as

$$R_{N^{(-1)}} = x - LA(D_x)$$

and

$$R_{A^{(-1)}} = x - LN(D_x).$$

These reciprocities are equivalent to the convolution identities (with the Kronecker delta $\delta_n = 0^n$, $\delta_0=1$)

$$\sum_{k=0}^n A_n(u_1,...,u_k)N_{n-k}^{(-1)}(u_1,...,u_{n-k}) = \delta_n$$

and

$$\sum_{k=0}^n A_n^{(-1)}(u_1,...,u_k)N_{n-k}(u_1,...,u_{n-k}) = \delta_n.$$

For easy reference, the coefficients of the monomials of

1c) $[A]$ are

$$(-1)^{Se} \frac{1}{n+1}\frac{(n+Se)!}{n!} \frac{1}{e_1!e_2!\cdots e_n!}$$

$$ =(-1)^{Se} \frac{1}{n+1}\binom{n+Se}{Se} \binom{Se}{e_1,e_2,...,e_n}$$

$$ = \frac{1}{n+1}\binom{-n-1}{Se} \binom{Se}{e_1,e_2,...,e_n}$$

2c) $[N]$,

$$\frac{1}{n+1} \frac{(n+1)!}{(n+1-Se)!} \frac{1}{e_1!e_2!\cdots e_n!}$$

$$= \frac{1}{n+1} \binom{n+1}{Se} \binom{Se}{e_1,e_2,...,e_n}$$

3c) $[A^{(-1)}]$,

$$ \frac{-1}{n-1} \frac{(n-1)!}{(n-1-Se)!} \frac{1}{e_1!e_2!\cdots e_n!}$$

$$ = \frac{-1}{n-1} \binom{n-1}{Se} \binom{Se}{e_1,e_2,...,e_n}$$

$$ = \frac{1}{-n+1} \binom{n-1}{Se} \binom{Se}{e_1,e_2,...,e_n}$$

4c) $[N^{(-1)}] = [N]^{-1}$,

$$ - \; \frac{(n+Se-2)!}{(n-1)!} \frac{1}{e_1!e_2!\cdots e_n!}$$

$$ = - \; \frac{1}{n-1} \frac{(n+Se-2)!}{(n-2)!} \frac{1}{e_1!e_2!\cdots e_n!}$$

$$ = - \; \frac{1}{n-1} \binom{n+Se-2}{Se} \binom{Se}{e_1,e_2,...,e_n}$$

$$ = \frac{1}{-n+1} \binom{-n+1}{Se} \binom{Se}{e_1,e_2,...,e_n}.$$

Note the sign change $n$ to $-n$ transforms $A_n(u_1,...,u_n)$ to $A^{(-1)}_n(u_1,...,u_n)$ and $N_n(u_1,...,u_n)$ to $N^{(-1)}_n(u_1,...,u_n)$. There are different methods of deriving the polynomials which explain this simple change-in-sign duality (combinatorial reciprocity).


Some references in which I've already found subsets of $[LA],[LN],[ILA],[ILN]$ are

A) "Supplementary Exercises for Chapter 7 (symmetric functions) of Enumerative Combinatorics, vol. 2" by Richard P. Stanley (version of 4 June 2023), pg. 53, Exercise 133 d) contains $[LA]$ as well as does eqn. 2 on pg. 4 of "Parking functions and noncrossing partitions" by Stanley (1997).

B) "Jack polynomials" by Michel Lassalle (2009) , pg. 11, eqns. 4.7 and 4.8 contain $[ILA]$ and $[ILN]$.

C) "Symmetric functions" by Alain Lascoux (2001), eqn. 4.4.4 (f) on pg. 55 contains $[ILA]$ (his other manuscripts "Polynomials" and "Alphabet splitting" as well).

D) "Rational parking functions and Catalan numbers" by Drew Armstrong, Nicholas Loehr, and Gregory Warrington (2014), pg. 6, contains essentially $[ILA]$.

Note: These results can be extended to subsets of $[A],[A^{(1)}],[N],[N^{(-1}]$ indexed by $[A^{(m)}],[N^{(m)}]$ where $m$ is any integer. The factors $(pm 1 + \pm n)^p$ that occur in $[ILN]$ and $[ILA]$ could then likely be generalized to contain the characteristic polynomial of the m-extended Shi arrangement as discussed by Armstrong on pp. 22-3 of "Hyperplane Arrangements and Diagonal Harmonics", valuated at an integer.

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  • $\begingroup$ A closely related MO_Q question is "Log associahedra and log noncrossing partitions--raising ops and symmetric function theory for $A_n$" (mathoverflow.net/questions/443841/…) . $\endgroup$ Commented Jun 27, 2023 at 13:30
  • $\begingroup$ A reduction of $[LN]$ with $u_k=t$ is essentially A132813, reverse A103371. This reduction can be found in “Counting partitions by genus: a compendium of results” by Robert Coquereaux and, Jean-Bernard Zuber (arxiv.org/abs/2305.01100, June 23, 2023). See pg 16 and Table 1 on pg. 17. See also my blog post "Log Narayana polynomials and the raising ops for the noncrossing and special Schur partition polynomials" (tcjpn.wordpress.com/2023/04/02/…). $\endgroup$ Commented Sep 6, 2023 at 16:40

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