defined by the holes of the incoming partons).
Next each softer system to be merged is studied in turn. Its gluons are,
in decreasing <i>pT</i> order, inserted on the colour dipole <i>i,j</i>
that gives the smallest <i>(p_g p_i)(p_g p_j)/(p_i p_j)</i>, i.e. 
minimizes the "disturbance" on the existing dipole, in terms of 
<i>pT^2</i> or <i>Lambda</i> measure (string length). The insertion
of the gluon means that the old dipole is replaced by two new ones. 
Also the (rather few) quark-antiquark pairs that ca