The first sample shows that math works. I let the line be drawn to make the sample clearer. 
   \large
    \pstextpath[c]%
      {\pscurve[linecolor=gray](0,1)(4,3)(6,2)(9,0)(12,1)(15,1)}%
      {$S_\alpha=\Omega(\gamma_\beta)$ is a connected snarf and
      $B=(\otimes,\rightarrow,\theta)$ is Boolean left subideal.}

[c][linecolor=gray](0,1)(4,3)(6,2)(9,0)(12,1)(15,1) Sα = Ω(γβ) is a connected snarf and B = (⊗,→, θ) is Boolean left subideal. 

    \psset{linestyle=none}
    \pstextpath[c]{\psarcn(0,0){73pt}{180}{0}}%
      {Centre National de la}
    \pstextpath[c]{\psarc(0,0){73pt}{180}{0}}%
      {Recherche Scientifique}

linestyle=none [c](0,0)73pt1800Centre National de la [c](0,0)73pt1800Recherche Scientifique

[c](0,0)[linestyle=none](0,-6)41800$\textstyle \parbox{3.5in}{In principle, it is possible to use parbox, but let'... ... really happens. It seems hard to believe that someone would want to do this.}$