Möbius Inversion of Random Acyclic Directed Graphs

Suppose a random acyclic digraph has adjacency matrix A with independent columns or independent rows. Then the mean Möbius inverse of the zeta matrix I + A is the Möbius inverse of the mean zeta matrix, i.e., E[(I + A )^?1]=[I + E( A )]^?1.     

Binomial posets, Möbius inversion, and permutation enumeration

A unified method is presented for enumerating permutations of sets and multisets with various conditions on their descents, inversions, etc. We first prove several formal identities involving Möbius functions associated with binomial posets. We then show that for certain binomial posets these Möbius functions are related to problems in permutation enumeration. Thus, for instance, we can explain “why” the exponential generating function for alternating permutations has the simple form (1 + sin x)/(cos x). We can also clarify the reason for the ubiquitous appearance of e^x in connection with permutations of sets, and of ξ(s) in connection with permutations of multisets.     

Complex projective structures with maximal number of Möbius transformations

We consider complex projective structures on Riemann surfaces and their groups of projective automorphisms. We show that the structures achieving the maximal possible number of projective automorphisms allowed by their genus are precisely the Fuchsian uniformizations of Hurwitz surfaces by hyperbolic metrics. More generally we show that Galois Bely? curves are precisely those Riemann surfaces for which the Fuchsian uniformization is the unique complex projective structure invariant under the full group of biholomorphisms.     

An Inequality for the Möbius Function of a Geometric Lattice

An inequality is derived for the Möbius function of a finite geometric lattice L. Equality is characterized by the modularity of certain elements of L. Applications are given to other inequalities involving Whitney numbers, ordered bases, and maximal chains.     

Möbius transformation and a version of Schwarz lemma in octonionic analysis

The octonion is a generalization of complex to noncommutative and nonassociative space which has closed relation with exception geometries, wave equation, Yang‐Mills equations, black hole, string theory, and special relativity. In this paper, the Möbius transformation in this manner is first introduced, and some properties are discussed about the transformation in octonionic analysis. Some technique lemmas will be given to solve the problems caused by the weak form of associativity. These versions of Schwarz lemma and Schwarz‐Pick lemma are first studied in octonionic setting which will invoke integral representation formula for harmonic function and Möbius transformations. This will generalize the corresponding results which appear in the classical function theory to nonassociative space and may give new energy for the development of physics.     

Zur numerischen Lösung gewöhnlicher Differential-gleichungen mit Splines in einem Sonderfall

In an earlier paper [1] a general procedure has been presented to obtain polynomial spline approximations for the solution of the initial value problem for ordinary differential equations. In this paper the general procedure is described by an equivalent one step method. Furthermore two convergence theorems are proved for a special case which is not included in the general convergence or divergence theory given in [1].     

Bemerkungen zu meiner Arbeit “Zur Theorie stetiger Abbildungen in Funktionalräumen”

Ohne ZusammenfassungMath. Zeitschrift26, S. 47–65.