\def\LRsymprop{3.2.1} \def\taquinrule{3.3.1} \def\epspathrule{3.3.2} \def\epspathjdt{3.3.3} \def\epsinvthm{3.3.4} \def\epsconcatlemma{3.3.5} \def\epsrootopthm{3.3.6} \def\mpathrule{4.1.1} \def\mpathsym{4.1.2} \def\mpathjdt{4.1.3} \def\minvthm{4.1.4} \def\mconcatlemma{4.1.5} \def\mrootopthm{4.1.6} \def\psipathrule{4.2.1} \def\psipathsym{4.2.2} \def\psipathjdt{4.2.3} \def\psiinvthm{4.2.4} \def\psiconcatlemma{4.2.5} \def\psirootopthm{4.2.6} \def\firstineq{1} \def\secondineq{2} \def\plpathrule{5.1} \def\dirlemma{5.2} \def\plpathjdt{5.3} \def\plinvthm{5.4} \secno =6 \subsecno =-1 \proclno =4 \eqnumber =2 \pageno =23 \advancepageno