Definition interp (lvar : list (COLTpoint * positive)) (Default : COLTpoint) : positive -> COLTpoint := 
  fun p => list_assoc_inv COLTpoint positive positive_dec lvar p Default.Definition eq_tagged (lvar : list (COLTpoint * positive)) := lvar = lvar.

Lemma eq_eq_tagged : forall lvar, lvar = lvar -> eq_tagged lvar.