'From Iddo Lev\'s PhD Dissertation p108-109
:param index_counter: ``Counter`` for unique indices
:param glueFormulaFactory: ``GlueFormula`` for creating new glue formulas
:return: (``Expression``,list of ``GlueFormula``) for the compiled linear logic and any newly created glue formulas'

def compile_neg(self, index_counter, glueFormulaFactory):

    (a, a_new) = self.antecedent.compile_pos(index_counter, glueFormulaFactory)
    (c, c_new) = self.consequent.compile_neg(index_counter, glueFormulaFactory)
    fresh_index = index_counter.get()
    c.dependencies.append(fresh_index)
    new_v = glueFormulaFactory((u'v%s' % fresh_index), a, set([fresh_index]))
    return (c, ((a_new + c_new) + [new_v]))
