%------------------------------------------------------------------------------ % Here please write the date of submission of paper or its revisions: %------------------------------------------------------------------------------ % \documentclass[12pt, reqno]{amsart} \usepackage{amsmath, amsthm, amscd, amsfonts, amssymb, graphicx, color} \usepackage[bookmarksnumbered, colorlinks, plainpages]{hyperref} \textheight 22.5truecm \textwidth 14.5truecm \setlength{\oddsidemargin}{0.35in}\setlength{\evensidemargin}{0.35in} \setlength{\topmargin}{-.5cm} \newtheorem{theorem}{Theorem}[section] \newtheorem{lemma}[theorem]{Lemma} \newtheorem{proposition}[theorem]{Proposition} \newtheorem{corollary}[theorem]{Corollary} \theoremstyle{definition} \newtheorem{definition}[theorem]{Definition} \newtheorem{example}[theorem]{Example} \newtheorem{exercise}[theorem]{Exercise} \newtheorem{conclusion}[theorem]{Conclusion} \newtheorem{conjecture}[theorem]{Conjecture} \newtheorem{criterion}[theorem]{Criterion} \newtheorem{summary}[theorem]{Summary} \newtheorem{axiom}[theorem]{Axiom} \newtheorem{problem}[theorem]{Problem} \theoremstyle{remark} \newtheorem{remark}[theorem]{Remark} \numberwithin{equation}{section} \def\CF{{\mathcal F}} \def\CK{{\mathcal K}} \def\CH{{\mathcal H}} \def\CJ{{\mathcal J}} \def\CL{{\mathcal L}} \def\CO{{\mathcal O}} \def\CB{{\mathcal B}} \def\CU{{\mathcal U}} \def\CS{{\mathcal S}} \def\CP{{\mathcal P}} \def\a{{\mathfrak a}} \def\b{{\mathfrak b}} \def\m{{\mathbf m}} \def\n{{\mathbf n}} %\def\u{{\mathbf u}} \def\v{{\mathbf v}} \def\w{{\mathbf w}} \def\x{{\mathbf x}} \def\y{{\mathbf y}} \def\z{{\mathbf z}} \def\l{{\mathbf l}} \def\j{{\mathbf j}} %\def\h{{\mathbf h}} %\def\k{{\mathbf k}} %\def\p{{\mathbf p}} \def\h{{\mathfrak h}} \def\g{{\mathfrak g}} \def\u{{\mathfrak u}} \def\k{{\mathfrak k}} \def\p{{\mathfrak p}} \def\A{{\mathbb A}} \def\E{{\mathbb E}} \def\C{{\mathbb C}} \def\H{{\mathbb H}} \def\N{{\mathbb N}} \def\R{{\mathbb R}} \def\S{{\mathbb S}} \def\W{{\mathbb W}} \def\Z{{\mathbb Z}} \def\T{{\mathbb T}} \def\F{{\mathbb F}} \def\Nn{{\mathbb N^n}} \def\Rn{{\mathbb R}^{n}} \def\Cn{{\mathbb C}^n} \def\Hn{{{\mathbb H}^n}} \def\Lc{{L^1(\mathbb C^n)}} \def\Lh{{L^1(\mathbb H^n)}} \def\Lr{{L^2(\mathbb R^n)}} \def\BLR{{\mathcal B(L^2(\mathbb R^n))}} \def\llh{{L^{2}(\mathbb H^n)}} \def\lam{{\lambda}} \def\phab{{\overline{\Phi}_{\alpha \beta}}} \def\phba{{\overline{\Phi}_{\beta \alpha}}} \def\phmn{{\overline{\Phi}_{\mu \nu}}} \def\qab{{Q_{\alpha \beta}}} \def\qba{{Q_{\beta \alpha}}} \def\qac{{Q_{\alpha \gamma}}} \def\qca{{Q_{\gamma \alpha}}} \def\qbc{{Q_{\beta \gamma}}} \def\qmn{{Q_{\mu \nu}}} \def\qnm{{Q_{\nu \mu}}} \def\qbb{{Q_{\beta \beta}}} \def\qaa{{Q_{\alpha \alpha}}} \def\uaj{{u_{\alpha}^j}} \def\uak{u_{\alpha}^k} \def\vabj{{v_{\alpha,\beta}^j}} \def\vack{{v_{\alpha,\gamma}^k}} \def\vanj{{v_{\alpha,\nu}^j}} \def\uuaj{{U_{\alpha}^j}} \def\uuajs{{U_{\alpha}^{j*}}} \def\pn{{(2\pi)^{\frac{n}{2}}}} \def\pnn{{(2\pi)^{-\frac{n}{2}}}} \def\haj{{\mathcal{H}_{\alpha}^j}} \def\hak{{\mathcal{H}_{\alpha}^k}} \def\ha{{\mathcal{H}_{\alpha}}} \def\hap{{\mathcal{H}_{\alpha}^{\perp}}} \def\fl{{f^{\lambda}}} \def\gl{{g^{\lambda}}} \def\rzt{{R_{(z,t)}}} \def\rzo{{R_{(z,0)}}} \def\pl{{\pi_\lambda}} \def\plzts{{\pi_\lambda}(z,t)^*} \def\plzt{{\pi_{\lambda}(z,t)}} \def\plzos{{\pi_\lambda}(z,0)^*} \def\rl{{\rho_\lambda}} \def\ul{{U_\lambda}} \def\tl{{T_\lambda}} \def\sl{{S_\lambda}} \def\Fl{{F_\lambda}} \def\zt{{(z,t)}} \def\mzt{{(-z,-t)}} \def\zo{{(z,0)}} \def\ot{{(0,t)}} \def\ws{{(w,s)}} \def\eilt{{e^{i \lambda t}}} \def\emilt{{e^{-i \lambda t}}} \def\eils{{e^{i \lambda s}}} \def\emils{{e^{-i \lambda s}}} \def\plam{{\Phi_{\lambda}}} \def\flam{{F_{\lambda}}} \def\phsi{{\varphi, \psi}} \def\vl{{V^{\lambda}}} \def\nm{{\|}} \def\plots{{\pi_{\lambda}(0,t)^*}} \def\rot{{R_{(0,t)}}} \def\ot{{(0,t)}} \def\eps{{\varepsilon}} \def\1{\text{\bf {1}}} \def\bs{\backslash} \def\id{\mathop{\text{\rm{id}}}\nolimits} \def\im{\mathop{\text{\rm{im}}}\nolimits} \def\h{{\mathfrak h}} \def\oline{\overline} \def \la {\langle} \def \ra {\rangle} \def\Sp{\mathop{\text{\rm Sp}}\nolimits} \def\sspan{\operatorname{span}} \def\proj{\operatorname{proj}} \def\sign{\operatorname{sign}} \newcommand{\wt}{\widetilde} \newcommand{\wh}{\widehat} \DeclareMathOperator{\IM}{Im} \DeclareMathOperator{\esssup}{ess\,sup} \DeclareMathOperator{\meas}{meas} \input{mathrsfs.sty} \begin{document} \setcounter{page}{109} \noindent\parbox{2.95cm}{\includegraphics*[keepaspectratio=true,scale=0.125]{AFA.jpg}} \noindent\parbox{4.85in}{\hspace{0.1mm}\\[1.5cm]\noindent \qquad Ann. Funct. Anal. 3 (2012), no. 1, 109--120\\ {\footnotesize \qquad \textsc{\textbf{$\mathscr{A}$}nnals of \textbf{$\mathscr{F}$}unctional \textbf{$\mathscr{A}$}nalysis}\\ \qquad ISSN: 2008-8752 (electronic)\\ \qquad URL: \textcolor[rgb]{0.00,0.00,0.99}{www.emis.de/journals/AFA/} }\\[.5in]} \title[A characterisation of the Fourier transform on $\H^n$]{A characterisation of the Fourier transform on the Heisenberg group} \author[R. Lakshmi Lavanya, S. Thangavelu]{R. Lakshmi Lavanya$^1$$^{*}$ and S. Thangavelu$^2$} \address{$^{1}$ Ramanujan Institute for Advanced Study in Mathematics\\ $~$University of Madras\\ Chennai-600 005, India.} \email{\textcolor[rgb]{0.00,0.00,0.84}{rlakshmilavanya@gmail.com}} \address{$^{2}$ Department of Mathematics\\ Indian Institute of Science\\Bangalore-560 012, India.} \email{\textcolor[rgb]{0.00,0.00,0.84}{veluma@math.iisc.ernet.in}} \dedicatory{{\rm Communicated by O. Christensen}} \subjclass[2010]{Primary 46K05; Secondary 42A85, 43A32.} \keywords{Heisenberg group, Weyl transform, Heisenberg group Fourier $~$transform, Hermite functions.} \date{Received: 2 November 2011; Accepted: 6 February 2012. \newline \indent $^{*}$ Corresponding author} \begin{abstract} The aim of this paper is to show that any $~$continuous $*$-homomorphism of $L^1(\C^n)$(with twisted convolution as multiplication) into $\CB(L^2(\Rn))$ is $~$essentially a Weyl transform. From this we deduce a similar characterisation for the group Fourier $~$transform on the Heisenberg group, in terms of convolution. \end{abstract} \maketitle \vspace{2in} \end{document} .