A large family of cospectral Cayley graphs over dicyclic groups

For a finite group G and an inverse closed subset $S\subseteq G\setminus \{e\}$, the Cayley graph $X(G,S)$ has vertex set G and two vertices $x,y\in G$ are adjacent if and only if $x{y}^{-1}\in S$. Two graphs are called cospectral if their adjacency matrices have the same spectrum. Let $p\ge 3$ be a prime number and $T_{4p}$ be the dicyclic group of order 4p. In this paper, with the help of the characters from representation theory, we construct a large family of pairwise non-isomorphic and cospectral Cayley graphs over the dicyclic group $T_{4p}$ with $p\ge 23$, and find several pairs of non-isomorphic and cospectral Cayley graphs for $5\le p\le 19$.     

Distributional inequalities for noncommutative martingales

We establish distributional estimates for noncommutative martingales, in the sense of decreasing rearrangements of the spectra of unbounded operators, which generalises the study of distributions of random variables. Our results include distributional versions of the noncommutative Stein, dual Doob, martingale transform and Burkholder-Gundy inequalities. Our proof relies upon new and powerful extrapolation theorems. As an application, we obtain some new martingale inequalities in symmetric quasi-Banach operator spaces and some interesting endpoint estimates. Our main approach demonstrates a method to build the noncommutative and classical probabilistic inequalities in an entirely operator theoretic way.     

ON HILBERT BOUNDARY VALUE PROBLEMS WITH RADICAL

The Hilbert boundary value problemRe{λ(t) P√ψ (t)} = c(t), t ∈ Lof normal type with Holder continuous coefficients is discussed, where Lis the unit circle |t| = 1,p ≥ 2 is any definite integer, Ψ (t) is the boundary value of the unknown function Ψ (z) holomorphic in |z| ＜ 1 with single-valued continuous P√ψ (t)} on L.     

Two families of constant term identities

The Ramanujan Journal - In 1985, Bressoud and Goulden derived the formula for the constant term in $$\prod _{(i,j)\in T} \frac{x_j}{x_i} \prod _{0\le i     

Vertex-transitive Diameter Two Graphs

We investigate the family of vertex-transitive graphs with diameter 2. Let Γ be such a graph.Suppose that its automorphism group is transitive on the set of ordered non-adjacent vertex pairs. Then either Γ is distance-transitive or Γ has girth at most 4. Moreover, if Γ has valency 2, then Γ≌ C₄ or C₅; and for any integer n ≥ 3, there exist such graphs Γ of valency n such that its automorphism group is not transitive on the set of arcs. Also, we determine this family of grap...     

Characterizations of plurisubharmonic functions

Science China Mathematics - We give characterizations of (quasi-)plurisubharmonic functions in terms of Lp-estimates of $\overline{\partial}$ and Lp-extensions of holomorphic functions.