For each orbit of faces of codimension k we give a canonical representative face f_i.
The face fk_i is defined by a set of k inequalities of rank k satisfied with equality.

A triangular inequality Tr of met_n is represented by a {-1,0,1}-valued vector V of
length n with 3 nonzero entries with: Tr_ij = V_i x V_j. The left hand side of Tr 
is 2 if V is a {0,1}-valued vector and 0 otherwise.

+++++ remark ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
the set of all inequalities satisfied with equality by f_i might be larger than k
but we show only k facets. This way the codimension is directly readable and the
presentation is homogeneous)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


-------------- canonical representatives --------------------------
f2_1

  1  1  1  0
  1  1  0  1
 
f2_2

  1  1  1  0  0
  1  0  0  1  1
 
f2_3

  1  1  1  0  0  0
  0  0  0  1  1  1