A series of seven new complexes of zirconium and hafnium with bulky ω-aryloxyalkyl substituted indenyl ligands were synthesized and characterized by NMR spectroscopy and elemental analysis. These complexes were activated with methylaluminoxane and tested for homogeneous ethylene polymerization. The zirconium catalysts showed higher activities than their hafnium an...

We use a systematic construction method for invariant connections on homogeneous spaces to find the Einstein-SU (n)-Yang-Mills equations for Friedmann-Robertson-Walker and locally rotationally symmetric homogeneous cosmologies. These connections depend on the choice of a homomorphism from the isotropy group into the gauge group. We consider here the cases of the gauge group SU (n) and SO(n) whe...

Let G be a connected reductive group. Recall that a homogeneous G-space X is called spherical if a Borel subgroup B ⊂ G has an open orbit on X . To X one assigns certain combinatorial invariants: the weight lattice, the valuation cone and the set of B-stable prime divisors. We prove that two spherical homogeneous spaces with the same combinatorial invariants are equivariantly isomorphic. Furthe...

We consider those projective bundles (or Brauer-Severi varieties) over an abelian variety that are homogeneous, i.e., invariant under translation. We describe the structure of these bundles in terms of projective representations of commutative group schemes; the irreducible bundles correspond to Heisenberg groups and their standard representations. Our results extend those of Mukai on semi-homo...

A homogeneous space X = G/H of a connected Lie group G is called a symmetric homogeneous space if there exists an involution σ of G such that H lies between the fixed point group G and its identity component Go . Example 0. For a connected Lie group G′, put G = G′×G′, σ(g1, g2) ) = (g2, g1) and H = G. Then the homogeneous space X = G/H is naturally isomorphic to G′ by the map (g1, g2) 7→ g1g−1 ...

A homogeneous graph is a graph together with a group which acts transitively on vertices as symmetries of the graph. We consider Laplacians of homogeneous graphs and generalizations of Laplacians whose eigenvalues can be associated with various equilibria of forces in molecules (such as vibrational modes of buckyballs). Methods are given for calculating such eigenvalues by combining concepts an...

Two studies investigated how group variability affects reactions to atypical group members. In Study 1 (N = 65) we manipulated group variability and found that an atypical group member was evaluated more positively when the group was heterogeneous than when the group was homogeneous. In Study 2 (N = 276) we also manipulated group value and found a significant interaction whereby an atypical gro...

A simple method for the preparation of homogeneous molecular species of plasmenylcholine and plasmenylethanolamine was developed. The method utilized reverse phase high performance liquid chromatography to isolate homogeneous molecular species of plasmenylcholine prepared by acylation of lysoplasmenylcholine. Plasmenylcholine was directly converted to plasmenylethanolamine by transphosphatidyla...