arXiv subjects
Publications and source records attributed to Goutam Satpati.
In this article, we obtain quasiconformal extensions of some classes of conformal maps defined either on the unit disc or on the exterior of it onto the extended complex plane. Some of these extensions have been obtained by constructing suitable Loewner chains and others have been obtained by applying a well-known result.
Let $Σ_k(p)$ be the class of univalent meromorphic functions defined on $\mathbb{D}$ with $k$-quasiconformal extension to the extended complex plane $\widehat{\mathbb{C}}$, where $0\leq k < 1$. Let $Σ_k^0(p)$ be the class of functions $f \in Σ_k(p)$ having expansion of the form $f(z)= 1/(z-p) + \sum_{n=1}^{\infty}b_n z^{n}$ on $\mathbb{D}$. In this article, we obtain sharp area distortion and weighted area distortion inequalities for functions in $Σ_k^0(p)$. As a consequence of the obtained results, we present a sharp estimate for the bounds of the Hilbert transform.
We consider the class $Σ(p)$ of univalent meromorphic functions $f$ on $\ID$ having simple pole at $z=p\in[0,1)$ with residue 1. Let $Σ_k(p)$ be the class of functions in $Σ(p)$ which have $k$-quasiconformal extension to the extended complex plane $\sphere$ %with $q=\frac{1+k}{1-k}$ where $0\leq k < 1$. We first give a representation formula for functions in this class and using this formula we derive an asymptotic estimate of the Laurent coefficients for the functions in the class $Σ_k(p)$. Thereafter we give a sufficient condition for functions in $Σ(p)$ to belong in the class $Σ_k(p).$ Finally we obtain a sharp distortion result for functions in $Σ(p)$ and as a consequence, we get a distortion estimate for functions in $Σ_k(p).$
In this note, we consider meromorphic univalent functions $f(z)$ in the unit disc with a simple pole at $z=p\in(0,1)$ which have a $k$-quasiconformal extension to the extended complex plane $\hat{\mathbb C},$ where $0\leq k < 1$. We denote the class of such functions by $Σ_k(p)$. We first prove an area theorem for functions in this class. Next, we derive a sufficient condition for meromorphic functions in the unit disc with a simple pole at $z=p\in(0,1)$ to belong to the class $Σ_k(p)$. Finally, we give a convolution property for functions in the class $Σ_k(p)$.