
  <span class='no'>formula</span>,
  <span class='no'>data</span>,
  <span class='no'>phy</span>,
  <span class='kw'>Vy</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>Vx</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>y.transf</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>x.transf</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>n.intra</span> <span class='kw'>=</span> <