diff --git a/src/jpg/comm2.57 b/src/jpg/comm2.57
index df218209..d43e15a9 100644
--- a/src/jpg/comm2.57
+++ b/src/jpg/comm2.57
@@ -4,9 +4,12 @@
 
 (macsyma-module comm2)
 
-(DECLARE (GENPREFIX CC) (SPECIAL $PROPS) (FIXNUM N I J))
-
-(DECLARE (SPLITFILE DIFF2) (SPECIAL $DOTDISTRIB))
+(DECLARE (GENPREFIX CC)
+         (SPECIAL $PROPS $DOTDISTRIB)
+         (FIXNUM N I J)
+         (SPLITFILE DIFF2)
+         (*expr hand-side freeofl gensumindex constant newvar badfunchk mapatom
+                getalias string*))
 
 (DEFMFUN DIFFINT (E X)
        ((LAMBDA (A)
@@ -30,6 +33,23 @@
       (LIST (IF (ZEROP U) 0 (MUL2 U (SUBSTITUTE (CADDDR E) Y (CAR E))))
 	    (IF (ZEROP V) 0 (MUL3 V (SUBSTITUTE (CADDR E) Y (CAR E)) -1)))))
 
+(DEFMFUN DIFFSUMPROD (E X)
+         (COND ((OR (NOT (ATOM X))
+                    (NOT (FREE (CADDDR E) X))
+                    (NOT (FREE (CAR (CDDDDR E)) X)))
+                (DIFF%DERIV (LIST E X 1)))
+               ((EQ (CADDR E) X) 0)
+               (T (LET ((U (SDIFF (CADR E) X)))
+                       (SETQ U (SIMPLIFYA (LIST '(%SUM)
+                                                (IF (EQ (CAAR E) '%SUM)
+                                                    U
+                                                    (DIV U (CADR E)))
+                                                (CADDR E)
+                                                (CADDDR E)
+                                                (CAR (CDDDDR E)))
+                                          T))
+                       (IF (EQ (CAAR E) '%SUM) U (MUL2 E U))))))
+
 (DEFMFUN DIFFSUM (E X)
  (COND ((OR (NOT (ATOM X)) (NOT (FREE (CADDDR E) X)) (NOT (FREE (CAR (CDDDDR E)) X)))
 	(DIFF%DERIV (LIST E X 1)))
@@ -41,6 +61,13 @@
  (COND ((OR (NOT (ATOM X)) (EQ (CADDDR E) X)) (DIFF%DERIV (LIST E X 1)))
        ((EQ (CADDR E) X) 0)
        (T ($LAPLACE (SDIFF (CADR E) X) (CADDR E) (CADDDR E)))))
+
+(DEFMFUN DIFF-%AT (E X)
+         (COND ((FREEOF X E) 0)
+               ((NOT (FREEOFL X (HAND-SIDE (CADDR E) 'R)))
+                (DIFF%DERIV (LIST E X 1)))
+               (T ($AT (SDIFF (CADR E) X) (CADDR E)))))
+
 
 (DEFMFUN DIFFNCEXPT (E X)
  ((LAMBDA (BASE* POW)