At the center of the theory of abelian p-groups are the classical theorems of Ulm, Zippin and Kaplansky, going back to the thirties, that classify countable p-groups by their Ulm invariants: the uniqueness theorem is referred to as Ulm's theorem, the existence theorem as Zippin's theorem. For each ordinal , the -th Ulm invariant of G can be de ned as the dimension fG( ) of the vector space (ove...

New time dependent wave solutions to the classical homogeneous Maxwell equations in the vacuum have been found. These waves are not transverse; they exhibit both torsion and spin; they have ̄nite magnetic helicity, A ± B 6= 0, a non-zero Poynting vector, E £H 6= 0;and a non zero second Poincare invariant, E ± B 6= 0: Two four component rank 3 tensors, constructed on topological grounds in terms ...

This paper makes certain observations regarding some conjectures of Milnor and Ramakrishnan in hyperbolic geometry and algebraic K-theory. As a consequence of our observations, we obtain new results and conjectures regarding the rationality and irrationality of Chern-Simons invariants of hyperbolic 3-manifolds. In this paper, by a hyperbolic 3-manifold, we shall mean a complete, oriented hyperb...

‎In this paper‎, ‎we study translation invariant surfaces in the‎ ‎3-dimensional Heisenberg group $rm Nil_3$‎. ‎In particular‎, ‎we‎ ‎completely classify translation invariant surfaces in $rm Nil_3$‎ ‎whose position vector $x$ satisfies the equation $Delta x = Ax$‎, ‎where $Delta$ is the Laplacian operator of the surface and $A$‎ ‎is a $3 times 3$-real matrix‎.

We provide examples of left-invariant unit vector fields on Lie groups.

Let $F$ be a left invariant Randers metric on simply connected nilpotent Lie group $N$, induced by Riemannian ${\hat{\textbf{\textit{a}}}}$ and vector field $X$ which is $I_{\hat{\textbf{\textit{a}}}}(M)$-invariant. If the Ricci flow equation has unique solution then, $(N,F)$ soliton if only semialgebraic soliton.

In this paper, we investigate the concept of topological stationary for locally compact semigroups. In [4], T. Mitchell proved that a semigroup S is right stationary if and only if m(S) has a left Invariant mean. In this case, the set of values ?(f) where ? runs over all left invariant means on m(S) coincides with the set of constants in the weak* closed convex hull of right translates of f. Th...

‎in this paper‎, ‎we study translation invariant surfaces in the‎ ‎3-dimensional heisenberg group $rm nil_3$‎. ‎in particular‎, ‎we‎ ‎completely classify translation invariant surfaces in $rm nil_3$‎ ‎whose position vector $x$ satisfies the equation $delta x = ax$‎, ‎where $delta$ is the laplacian operator of the surface and $a$‎ ‎is a $3 times 3$-real matrix‎.