Let K(n) be the nth Morava K-theory spectrum. Let En be the Lubin-Tate spectrum, which plays a central role in understanding LK(n)(S 0), the K(n)-local sphere. For any spectrum X, define E∨(X) to be the spectrum LK(n)(En ∧ X). Let G be a closed subgroup of the profinite group Gn, the group of ring spectrum automorphisms of En in the stable homotopy category. We show that E∨(X) is a continuous G...

Kleinewillinghöfer types of Laguerre planes reflect transitivity properties of certain groups of central automorphisms. In the case of flat Laguerre planes, Polster and Steinke have shown that some of the conceivable types cannot exist, and they gave models for most of the other types. Only few types are still in doubt. One of them is type V.A.1, whose existence we prove here. In order to const...

The automorphisms of free groups with boundaries form a family of groups An,k closely related to mapping class groups, with the standard automorphisms of free groups as An,0 and (essentially) the symmetric automorphisms of free groups as A0,k . We construct a contractible space Ln,k on which An,k acts with finite stabilizers and finite quotient space and deduce a range for the virtual cohomolog...

Let $\mathcal{C}$ be a smooth, projective, genus $g\geq 2$ curve, defined over $\mathbb{C}$. Then has \emph{many automorphisms} if its corresponding moduli point $p \in \mathcal{M}_g$ neighborhood $U$ in the complex topology, such that all curves to points $U \setminus \{p \}$ have strictly fewer automorphisms than $\mathcal{C}$. We compute completely list of superelliptic having many automorph...

Klein and Kroll classified Minkowski planes with respect to subgroups of central automorphisms and obtained a multitude of types. Some of these types are known to exist only in finite Minkowski planes or as the type of a proper subgroup in the automorphism group. In this paper we investigate the Klein– Kroll types of flat Minkowski planes with respect to the full automorphism groups of these pl...

The involutions in this paper are algebra anti-automorphisms of period two. Involutions on endomorphism algebras of finite-dimensional vector spaces are adjoint to symmetric or skew-symmetric bilinear forms, or to hermitian forms. Analogues of the classical invariants of quadratic forms (discriminant, Clifford algebra, signature) have been defined for arbitrary central simple algebras with invo...

Let G be a connected Lie group acting by algebra automorphisms on a finite-dimensional complex central simple algebra A. The algebra A is isomorphic to the endomorphism algebra of a projective representation V of G. We study the invariant subalgebras of A. In particular, we show that if V is irreducible, then the invariant subalgebras appear in dual pairs arising from factorizations of V . We a...

In this article, we study geometric unitaries of JB-algebras (in particular, self-adjoint parts of C∗-algebras). We will show that the geometric unitaries of a JB algebra are precisely those central algebraic unitaries (or central symmetries). We will also show that the group of surjective isometries on a JB-algebra A (with point-norm topology) is the semi-direct product of the canonical action...

By considering constraints on the dimensions of the Lie algebra corresponding to the weight one states of Z 2 and Z 3 orbifold models arising from imposing the appropriate modular properties on the graded characters of the automorphisms on the underlying conformal field theory, we propose a set of constructions of all but one of the 71 self-dual meromorphic bosonic conformal field theories at c...

We prove severaìautomatic' ergodicity results for cocycles on a discrete nonsingular ergodic equivalence relation on a probability space (X; S;) with values in virtually nilpotent groups. The hypotheses required for automatic ergodicity are invari-ance or quasi-invariance of the cocycles under asymptotically central automorphisms of the equivalence relation. If the cocycles have certain recurre...