Generalizations of Milne’s U(n + 1) q-Chu-Vandermonde summation

We derive two identities for multiple basic hyper-geometric series associated with the unitary U(n+1) group. In order to get the two identities, we first present two known q-exponential operator identities which were established in our earlier paper. From the two identities and combining them with the two U(n + 1) q-Chu-Vandermonde summations established by Milne, we arrive at our results. Using the identities obtained in this paper, we give two interesting identities involving binomial coefficients. In addition, we also derive two nontrivial summation equations from the two multiple extensions.     

Identities for partial Bell polynomials derived from identities for weighted integer compositions

We discuss closed-form formulas for the (n, k)th partial Bell polynomials derived in Cvijovi? (Appl Math Lett 24:1544–1547, 2011). We show that partial Bell polynomials are special cases of weighted integer compositions, and demonstrate how the identities for partial Bell polynomials easily follow from more general identities for weighted integer compositions. We also provide short and elegant probabilistic proofs of the latter, in terms of sums of discrete integer-valued random variables. Finally, we outline further identities for the partial Bell polynomials.     

Generalized Pleijel identity

A family of identities primarily associated with isoperimetric inequalities for planar convex domains was discovered by Pleijel in 1956. We call these identities classical Pleijel identities. R. V. Ambartzumian gave combinatorial proof of these identities and pointed out that they can be applied to find chord length distribution functions for convex domains. In the classical Pleijel identities integration is over the measure in the space \(\mathbb{G}\) of lines which is invariant with respect to the all Euclidean motions. In the present paper they are considered for any locally-finite measure in the space \(\mathbb{G}\). These identities are applied to find the so-called orientation-dependent chord length distribution (or density) functions for bounded convex domains.     

Generalized <Emphasis Type="BoldItalic">r</Emphasis>-Lah numbers

In this paper, we consider a two-parameter polynomial generalization, denoted by \(\mathcal {G}_{a,b}(n,k;r)\), of the r-Lah numbers which reduces to these recently introduced numbers when a = b = 1. We present several identities for \(\mathcal {G}_{a,b}(n,k;r)\) that generalize earlier identities given for the r-Lah and r-Stirling numbers. We also provide combinatorial proofs of some earlier identities involving the r-Lah numbers by defining appropriate sign-changing involutions. Generalizing these arguments yields orthogonality-type relations that are satisfied by \(\mathcal {G}_{a,b}(n,k;r)\).     

Complex variables and flexure

We introduce several advanced trigonometric and complex variables identities. These identities are used in solving the flexure problem of beams with cross sections which are given byr=[sin(/2n)]²ⁿ . These identities and solutions generalize several previous results.Dedicated to Professor M. M. Abbassi     

A Bailey lattice

We exhibit a technique for generating new Bailey pairs which leads to deformations of classical -series identities, multiple series identities of the Rogers-Ramanujan type, identities involving partial theta functions, and a variety of representations for -series by number-theoretic objects such as weight 3/2 modular forms, ternary quadratic forms, and weighted binary quadratic forms.

     

Partition identities and geometric bijections

We present a geometric framework for a class of partition identities. We show that there exists a unique bijection proving these identities, which satisfies certain linearity conditions. In particular, we show that Corteel's bijection enumerating partitions with nonnegative -th differences can be obtained by our approach. Other examples and generalizations are presented.

     

The identities of the free product of two trivial semigroups

We exhibit an example of a finitely presented semigroup S with a minimum number of relations such that the identities of S have a finite basis while the monoid obtained by adjoining 1 to S admits no finite basis for its identities. Our example is the free product of two trivial semigroups.     

Arithmetic properties arising from Ramanujan’s theta functions

We prove some interesting arithmetic properties of theta function identities that are analogous to q-series identities obtained by Michael D. Hirschhorn. In addition, we find infinite family of congruences modulo powers of 2 for representations of a non-negative integer n as \(\triangle _1+4\triangle _2\) and \(\triangle +k\square \).     

An algorithmic proof theory for hypergeometric (ordinary and “q”) multisum/integral identities

Summary It is shown that every proper-hypergeometric multisum/integral identity, orq-identity, with a fixed number of summations and/or integration signs, possesses a short, computer-constructible proof. We give a fast algorithm for finding such proofs. Most of the identities that involve the classical special functions of mathematical physics are readily reducible to the kind of identities treated here. We give many examples of the method, including computer-generated proofs of identities of Mehta-Dyson, Selberg, Hille-Hardy,q-Saalschütz, and others. The prospect of using the method for proving multivariate identities that involve an arbitrary number of summations/integrations is discussed.Supported in part by the U.S. Office of Naval ResearchSupported in part by the U.S. National Science Foundation     

Partition identities arising from Ramanujan’s formulas for multipliers

We find new partition identities arising from Ramanujan’s formulas of multipliers. Several of the identities are for overpartitions, overpartition pairs, and \(\ell \)-regular partitions.     

Bases of identities for semigroups of bounded rank transformations of a set

We complete the series of results by M. V. Sapir, M. V. Volkov and the author solving the Finite Basis Problem for semigroups of rank ≤ k transformations of a set, namely based on these results we prove that the semigroup T _k (X) of rank ≤ k transformations of a set X has no finite basis of identities if and only if k is a natural number and either k = 2 and |X| ∈ «3, 4» or k ≥ 3. A new method for constructing finite non-finitely based semigroups is developed. We prove that the semigroup of rank ≤ 2 transformations of a 4-element set has no finite basis of identities but that the problem of checking its identities is tractable (polynomial).     

Some Combinatorial and Analytical Identities

We give new proofs and explain the origin of several combinatorial identities of Fu and Lascoux, Dilcher, Prodinger, Uchimura, and Chen and Liu. We use the theory of basic hypergeometric functions, and generalize these identities. We also exploit the theory of polynomial expansions in the Wilson and Askey-Wilson bases to derive new identities which are not in the hierarchy of basic hypergeometric series. We demonstrate that a Lagrange interpolation formula always leads to very-well-poised basic hypergeometric series. As applications we prove that the Watson transformation of a balanced ${_{4}\phi_{3}}$ to a very-well-poised ${_{8}\phi_{7}}$ is equivalent to the Rodrigues-type formula for the Askey-Wilson polynomials. By applying the Leibniz formula for the Askey-Wilson operator we also establish the ${_{8}\phi_{7}}$ summation theorem.     

Certain Somos’s $$\varvec{}$$–$$\varvec{Q}$$Q type Dedekind $$\varvec{\eta }$$η-function identities

In this paper, we provide a new proof for the Dedekind \(\eta \)-function identities discovered by Somos. During this process, we found two new Dedekind \(\eta \)-function identities. Furthermore, we extract interesting partition identities from some of the \(\eta \)-function identities.     

A theta function identity and its implications

In this paper we prove a general theta function identity with four parameters by employing the complex variable theory of elliptic functions. This identity plays a central role for the cubic theta function identities. We use this identity to re-derive some important identities of Hirschhorn, Garvan and Borwein about cubic theta functions. We also prove some other cubic theta function identities. A new representation for is given. The proofs are self-contained and elementary.

     

An application of lattice basis reduction to polynomial identities for algebraic structures

The authors’ recent classification of trilinear operations includes, among other cases, a fourth family of operations with parameter $q\in \mathbb{Q}\cup \{\infty \}$, and weakly commutative and weakly anticommutative operations. These operations satisfy polynomial identities in degree 3 and further identities in degree 5. For each operation, using the row canonical form of the expansion matrix E to find the identities in degree 5 gives extremely complicated results. We use lattice basis reduction to simplify these identities: we compute the Hermite normal form H of E^t, obtain a basis of the nullspace lattice from the last rows of a matrix U for which UE^t = H, and then use the LLL algorithm to reduce the basis.     

Restricted partition functions and identities for degrees of syzygies in numerical semigroups

We derive a set of polynomial and quasipolynomial identities for degrees of syzygies in the Hilbert series of numerical semigroup \(\langle d_1,\ldots ,d_m\rangle \), \(m\ge 2\), generated by an arbitrary set of positive integers \(\left\{ d_1, \ldots ,d_m\right\} \), \(\gcd (d_1,\ldots ,d_m)=1\). These identities are obtained by studying the rational representation of the Hilbert series and the quasipolynomial representation of the Sylvester waves in the restricted partition function. In the cases of symmetric semigroups and complete intersections, these identities become more compact; for the latter we find a simple identity relating the degrees of syzygies with elements of generating set \(\left\{ d_1,\ldots ,d_m\right\} \) and give a new lower bound for the Frobenius number.     

Poisson PI algebras

We study Poisson algebras satisfying polynomial identities. In particular, such algebras satisfy ``customary' identities (Farkas, 1998, 1999) Our main result is that the growth of the corresponding codimensions of a Poisson algebra with a nontrivial identity is exponential, with an integer exponent. We apply this result to prove that the tensor product of Poisson PI algebras is a PI-algebra. We also determine the growth of the Poisson-Grassmann algebra and of the Hamiltonian algebras .

     

Basic series identities and combinatorics

Analogous to P.A. MacMahon’s combinatorial interpretations of the Rogers–Ramanujan identities, we interpret two basic series identities combinatorially in two different ways—using split \((n+t)\)-color partitions and the modified lattice paths. This leads to two new 3-way combinatorial identities. We conclude by posing three significant open problems.