repeat split;intros;try (rewrite sizes_comm_l||rewrite sizes_comm_r);
apply plus_lt_compat_l||apply plus_lt_compat_r;induction Γ1||induction Δ1;
unfold sizel;simpl;try (apply plus_lt_compat_l;apply IHΓ1||apply IHΔ1);
apply le_lt_n_Sm;rewrite <- plus_assoc;try constructor;
try apply plus_le_compat_l;apply le_plus_trans_r;constructor.
Qed.

(* Specifications: *)
Lemma size_O_atomic : forall Γ, sizel Γ=0 -> exists l, Γ = map AtomicF l.
intros;induction Γ.