diff --git a/colim.hlean b/colim.hlean
index bdb571e..7619b49 100644
--- a/colim.hlean
+++ b/colim.hlean
@@ -399,7 +399,7 @@ namespace seq_colim
   equiv.mk _ !is_equiv_seq_colim_rec
   end functor
 
-  definition pseq_colim.elim [constructor] {A : ℕ → Type*} {B : Type*} {f : Π{n}, A n →* A (n+1)}
+  definition pseq_colim.elim' [constructor] {A : ℕ → Type*} {B : Type*} {f : Π{n}, A n →* A (n+1)}
     (g : Πn, A n →* B) (p : Πn, g (n+1) ∘* f ~ g n) : pseq_colim @f →* B :=
   begin
     fapply pmap.mk,
@@ -409,6 +409,10 @@ namespace seq_colim
     { esimp, apply respect_pt }
   end
 
+  definition pseq_colim.elim [constructor] {A : ℕ → Type*} {B : Type*} {f : Π{n}, A n →* A (n+1)}
+    (g : Πn, A n →* B) (p : Πn, g (n+1) ∘* f ~* g n) : pseq_colim @f →* B :=
+  pseq_colim.elim' g p
+
   definition prep0 [constructor] {A : ℕ → Type*} (f : pseq_diagram A) (k : ℕ) : A 0 →* A k :=
   pmap.mk (rep0 (λn x, f x) k)
           begin induction k with k p, reflexivity, exact ap (@f k) p ⬝ !respect_pt end
diff --git a/homotopy/spectrum.hlean b/homotopy/spectrum.hlean
index 597fa76..5f39b59 100644
--- a/homotopy/spectrum.hlean
+++ b/homotopy/spectrum.hlean
@@ -431,8 +431,15 @@ namespace spectrum
   -- note: the forward map is (currently) not definitionally equal to gluen. Is that a problem?
   definition equiv_gluen {N : succ_str} (X : gen_spectrum N) (n : N) (k : ℕ)
     : X n ≃* Ω[k] (X (n +' k)) :=
-  by induction k with k f; reflexivity; exact f ⬝e* loopn_pequiv_loopn k (equiv_glue X (n +' k))
-                                                ⬝e* !loopn_succ_in⁻¹ᵉ*
+  by induction k with k f; reflexivity; exact f ⬝e* (loopn_pequiv_loopn k (equiv_glue X (n +' k))
+                                                ⬝e* !loopn_succ_in⁻¹ᵉ*)
+
+  definition equiv_gluen_inv_succ {N : succ_str} (X : gen_spectrum N) (n : N) (k : ℕ) :
+    (equiv_gluen X n (k+1))⁻¹ᵉ* ~*
+    (equiv_gluen X n k)⁻¹ᵉ* ∘* Ω→[k] (equiv_glue X (n +' k))⁻¹ᵉ* ∘* !loopn_succ_in :=
+  begin
+    refine !trans_pinv ⬝* pwhisker_left _ _, refine !trans_pinv ⬝* _, refine !to_pinv_pequiv_MK2 ◾* !pinv_pinv
+  end
 
   definition spectrify_map {N : succ_str} {X : gen_prespectrum N} : X →ₛ spectrify X :=
   begin
@@ -457,7 +464,9 @@ namespace spectrum
     fapply smap.mk,
     { intro n, fapply pseq_colim.elim,
       { intro k, refine !equiv_gluen⁻¹ᵉ* ∘* apn k (f (n +' k)) },
-      { intro k, apply to_homotopy, exact sorry }},
+      { intro k, refine !passoc ⬝* pwhisker_right _ !equiv_gluen_inv_succ ⬝* _,
+        refine !passoc ⬝* _, apply pwhisker_left,
+        refine !passoc ⬝* _, exact sorry }},
     { intro n, exact sorry }
   end