In this paper, we introduce the concept of the independence graph of a directed 2-complex. We show that the class of diagram groups is closed under graph products over independence graphs of rooted 2-trees. This allows us to show that a diagram group containing all countable diagram groups is a semi-direct product of a partially commutative group and R. Thompson's group F. As a result, we prove...

Let λ > 0 be a positive real number, and let n ≥ 1 be an integer. Let G = R×sR be a semi-direct product Lie group where the group multiplication in G is defined by (v1, x1) ∗ (v2, x2) = (v1 + ev2, x1 + x2) for all vi ∈ R, xi ∈ R, and i = 1, 2. We show G has constant sectional curvature −λ, and describe the irreducible unitary representations of G. 2010 Mathematic Subject Classification: 22D10, ...

Consider the semi-direct product Z ⋊ρ Z/m. A conjecture of Adem-Ge-Pan-Petrosyan predicts that the associated Lyndon-Hochschild-Serre spectral sequence collapses. We prove this conjecture provided that the Z/maction on Z is free outside the origin. We disprove the conjecture in general, namely, we give an example with n = 6 and m = 4, where the second differential does not vanish.

(2+2)–dimensional quantum mechanical q–phase space which is the semi– direct product of the quantum planeEq(2)/U(1) and its dual algebra eq(2)/u(1) is constructed. Commutation and the resulting uncertainty relations are studied. ”Quantum mechanical q–Hamiltonian” of the motion over the quantum plane is derived and the solution of the Schrödinger equation for the q– semiclassical motion governed...

The Jacobi group is the semi-direct product of the symplectic group and the Heisenberg group. The Jacobi group is an important object in the framework of quantum mechanics, geometric quantization and optics. In this paper, we study the Weil representations of the Jacobi group and their properties. We also provide their applications to the theory of automorphic forms on the Jacobi group and repr...

The notion of Asteroidal triples was introduced by Lekkerkerker and Boland [6]. D.G.Corneil and others [2], Ekkehard Kohler [3] further investigated asteroidal triples. Walter generalized the concept of asteroidal triples to asteroidal sets [8]. Further study was carried out by Haiko Muller [4]. In this paper we find asteroidal numbers for Direct product of cycles, Direct product of path and cy...