Definition eqPf :
  forall pq, {eqP (fst pq) (snd pq)} + {~ eqP (fst pq) (snd pq)}.Definition seqP : poly A0 eqA ltM -> poly A0 eqA ltM -> Prop.

Theorem seqp_sym : symmetric (poly A0 eqA ltM) seqP.