ﻻ يوجد ملخص باللغة العربية
It is well known that $G=langle x,y:x^2=y^3=1rangle$ represents the modular group $PSL(2,Z)$, where $x:zrightarrowfrac{-1}{z}, y:zrightarrowfrac{z-1}{z}$ are linear fractional transformations. Let $n=k^2m$, where $k$ is any non zero integer and $m$ is square free positive integer. Then the set $$Q^*(sqrt{n}):={frac{a+sqrt{n}}{c}:a,c,b=frac{a^2-n}{c}in Z~textmd{and}~(a,b,c)=1}$$ is a $G$-subset of the real quadratic field $Q(sqrt{m})$ cite{R9}. We denote $alpha=frac{a+sqrt{n}}{c}$ in $ Q^*(sqrt{n})$ by $alpha(a,b,c)$. For a fixed integer $s>1$, we say that two elements $alpha(a,b,c)$, $alpha(a,b,c)$ of $Q^*(sqrt{n})$ are $s$-equivalent if and only if $aequiv a(mod~s)$, $bequiv b(mod~s)$ and $cequiv c(mod~s)$. The class $[a,b,c](mod~s)$ contains all $s$-equivalent elements of $Q^*(sqrt{n})$ and $E^n_s$ denotes the set consisting of all such classes of the form $[a,b,c](mod~s)$. In this paper we investigate proper $G$-subsets and $G$-orbits of the set $Q^*(sqrt{n})$ under the action of Modular Group $G$
We count the finitely generated subgroups of the modular group $textsf{PSL}(2,mathbb{Z})$. More precisely: each such subgroup $H$ can be represented by its Stallings graph $Gamma(H)$, we consider the number of vertices of $Gamma(H)$ to be the size of
We show how to count and randomly generate finitely generated subgroups of the modular group $textsf{PSL}(2,mathbb{Z})$ of a given isomorphism type. We also prove that almost malnormality and non-parabolicity are negligible properties for these subgr
Let ${frak F}$ be a class of group and $G$ a finite group. Then a set $Sigma $ of subgroups of $G$ is called a emph{$G$-covering subgroup system} for the class ${frak F}$ if $Gin {frak F}$ whenever $Sigma subseteq {frak F}$. We prove that: {sl If a
A real valued function defined on}$mathbb{R}$ {small is called}$g${small --convex if it satisfies the following textquotedblleft generalized Jensens inequalitytextquotedblright under a given}$g${small -expectation, i.e., }$h(mathbb{E}^{g}[X])leq math
In this work the equivariant signature of a manifold with proper action of a discrete group is defined as an invariant of equivariant bordisms. It is shown that the computation of this signature can be reduced to its computation on fixed points sets