On canonical-type connections on almost contact complex Riemannian manifolds

We consider a pair of smooth manifolds, which are the counterparts in the even-dimensional and odd-dimensional cases. They are separately an almost complex manifold with Norden metric and an almost contact manifolds with B-metric, respectively. They can be combined as the so-called almost contact complex Riemannian manifold. This paper is a survey with additions of results on differential geometry of canonical-type connections (i.e. metric connections with torsion satisfying a certain algebraic identity) on the considered manifolds.

Some remarkable integrals derived from a simple algebraic identity

The identity in question really is simple: it says, for u ≠ −1,We describe two types of definite integral that look quite formidable, but dissolve into a much simpler form by an application of (1) in a way that seems almost magical.Both types, or at least special cases of them, have been mathematical folklore for a long time. For example, case (10) below appears in [1, p. 262], published in 1922 (we are grateful to Donald Kershaw for showing us this example). However, they do not seem to figure in most books on calculus except possibly tucked away as an exercise The comprehensive survey [2] mentions the second type on p. 253, but only as a lemma on the way to an identity the authors call the ‘master formula’ We come back to this formula later, but only after describing a number of other more immediate applications.

Skew Pieri Rules for Hall-Littlewood Functions

International audience We produce skew Pieri Rules for Hall–Littlewood functions in the spirit of Assaf and McNamara (FPSAC, 2010). The first two were conjectured by the first author (FPSAC, 2011). The key ingredients in the proofs are a q-binomial identity for skew partitions that are horizontal strips and a Hopf algebraic identity that expands products of skew elements in terms of the coproduct and antipode. Nous produisons quelques règles dissymètrique de Pieri pour les fonctions Hall–Littlewood au sens de Assaf et McNamara (FPSAC, 2010). Les premières deux règles ont ètè conjecturèe par le premier auteur (FPSAC, 2011). Les principaux ingrèdients dans les preuves sont une identitè q-binomiale pour les partitions dissymètrique qui sont bandes horizontales et une identitè de Hopf qui exprime les produits d'èlèments dissymètrique en termes du coproduit et de l'antipode.

Labeled Trees, Functions, and an Algebraic Identity

We give a short and direct proof of a remarkable identity that arises in the enumeration of labeled trees with respect to their indegree sequence, where all edges are oriented from the vertex with lower label towards the vertex with higher label. This solves a problem posed by Shin and Zeng in a recent article. We also provide a generalization of this identity that translates to a formula for the number of rooted spanning forests with given indegree sequence.