diff --git a/cfg_utils.py b/cfg_utils.py
index 6856ecb3c4ad6a5d04db977cead867860692dae0..7d18eb4f94d5722ae849567ca0b8a626da87e1b7 100644
--- a/cfg_utils.py
+++ b/cfg_utils.py
@@ -463,8 +463,18 @@ class CFGBoltzmann:
                 return [sum]
 
             else:
-                # CASE D (the full convolution)
-
+                # CASE D
+                # Here we must do the full convolution to account for every
+                # possible way that the total length of the desired string can
+                # be split between the nonterminal at X_ijk and the remaining
+                # segment of the rule (from k+1 to the end of the rule)
+
+                # Here, L will be the number of characters produced by X_ijk
+                # L will therefore go from 1 (we disallow epsilon-productions so
+                # X_ijk must produce at least one character) to:
+                # Total Characters Requested - (minimum number of characters generated by k+1 to end of rule)
+                # which will be:
+                # 
 
         return 0