diff --git a/books/bookvol9.pamphlet b/books/bookvol9.pamphlet
index f882776..28dd3f0 100644
--- a/books/bookvol9.pamphlet
+++ b/books/bookvol9.pamphlet
@@ -3628,6 +3628,37 @@ An angry JHD - August 15th., 1984
 
 @
 
+\defplist{is}{compIs}
+<<postvars>>=
+(eval-when (eval load)
+ (setf (get '|is| 'special) '|compIs|))
+
+@
+
+\defun{compIs}{compIs}
+\calls{compIs}{comp}
+\calls{compIs}{coerce}
+\usesdollar{compIs}{Boolean}
+\usesdollar{compIs}{EmptyMode}
+<<defun compIs>>=
+(defun |compIs| (arg m e)
+ (let (a b aval am tmp1 bval bm td)
+ (declare (special |$Boolean| |$EmptyMode|))
+  (setq a (CADR arg))
+  (setq b (CADDR arg))
+  (when (setq tmp1 (|comp| a |$EmptyMode| e))
+   (setq aval (CAR tmp1))
+   (setq am (CADR tmp1))
+   (setq e (CADDR tmp1))
+   (when (setq tmp1 (|comp| b |$EmptyMode| e))
+    (setq bval (CAR tmp1))
+    (setq bm (CADR tmp1))
+    (setq e (CADDR tmp1))
+    (setq td (list (list '|domainEqual| aval bval) |$Boolean| e ))
+    (|coerce| td m)))))
+
+@
+
 \defplist{+->}{compLambda}
 <<postvars>>=
 (eval-when (eval load)
@@ -10961,6 +10992,7 @@ if \verb|$InteractiveMode| then use a null outputstream
 <<defun compHas>>
 <<defun compIf>>
 <<defun compImport>>
+<<defun compIs>>
 <<defun compLambda>>
 <<defun compileFileQuietly>>
 <<defun compile-lib-file>>
diff --git a/changelog b/changelog
index c6c21f4..a907e36 100644
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+20101126 tpd src/axiom-website/patches.html 20101126.01.tpd.patch
+20101126 tpd src/interp/postprop.lisp treeshake compiler
+20101126 tpd src/interp/compiler.lisp treeshake compiler
+20101126 tpd books/bookvol9 treeshake compiler
 20101125 tpd src/axiom-website/patches.html 20101125.02.tpd.patch
 20101125 tpd books/bookvol9 treeshake compiler
 20101125 tpd src/axiom-website/patches.html 20101125.01.tpd.patch
diff --git a/src/axiom-website/patches.html b/src/axiom-website/patches.html
index 04cd661..76248d1 100644
--- a/src/axiom-website/patches.html
+++ b/src/axiom-website/patches.html
@@ -3274,5 +3274,7 @@ books/bookvol9 treeshake compiler<br/>
 books/bookvol9 treeshake compiler<br/>
 <a href="patches/20101125.02.tpd.patch">20101125.02.tpd.patch</a>
 books/bookvol9 treeshake compiler<br/>
+<a href="patches/20101126.01.tpd.patch">20101126.01.tpd.patch</a>
+books/bookvol9 treeshake compiler<br/>
  </body>
 </html>
diff --git a/src/interp/compiler.lisp.pamphlet b/src/interp/compiler.lisp.pamphlet
index cc69775..b1f1ef2 100644
--- a/src/interp/compiler.lisp.pamphlet
+++ b/src/interp/compiler.lisp.pamphlet
@@ -2573,39 +2573,6 @@ Compile return
                 |T'|)))))))))
 
 @
-\subsection{compIs}
-<<*>>=
-;compIs(["is",a,b],m,e) ==
-;  [aval,am,e] := comp(a,$EmptyMode,e) or return nil
-;  [bval,bm,e] := comp(b,$EmptyMode,e) or return nil
-;  T:= [["domainEqual",aval,bval],$Boolean,e]
-;  coerce(T,m)
-
-(DEFUN |compIs| (G170221 |m| |e|)
-  (PROG (|a| |b| |aval| |am| |LETTMP#1| |bval| |bm| T$)
-  (declare (special |$Boolean| |$EmptyMode|))
-    (RETURN
-      (PROGN
-        (COND ((EQ (CAR G170221) '|is|) (CAR G170221)))
-        (SPADLET |a| (CADR G170221))
-        (SPADLET |b| (CADDR G170221))
-        (SPADLET |LETTMP#1|
-                 (OR (|comp| |a| |$EmptyMode| |e|) (RETURN NIL)))
-        (SPADLET |aval| (CAR |LETTMP#1|))
-        (SPADLET |am| (CADR |LETTMP#1|))
-        (SPADLET |e| (CADDR |LETTMP#1|))
-        (SPADLET |LETTMP#1|
-                 (OR (|comp| |b| |$EmptyMode| |e|) (RETURN NIL)))
-        (SPADLET |bval| (CAR |LETTMP#1|))
-        (SPADLET |bm| (CADR |LETTMP#1|))
-        (SPADLET |e| (CADDR |LETTMP#1|))
-        (SPADLET T$
-                 (CONS (CONS '|domainEqual|
-                             (CONS |aval| (CONS |bval| NIL)))
-                       (CONS |$Boolean| (CONS |e| NIL))))
-        (|coerce| T$ |m|)))))
-
-@
 \section{Functions for coercion by the compiler}
 \subsection{coerce}
 The function coerce is used by the old compiler for coercions.
diff --git a/src/interp/postprop.lisp.pamphlet b/src/interp/postprop.lisp.pamphlet
index 64b8c8d..6d9ea2c 100644
--- a/src/interp/postprop.lisp.pamphlet
+++ b/src/interp/postprop.lisp.pamphlet
@@ -73,7 +73,7 @@
 ;          (|has|            |compHas|)
 ;          (IF               |compIf|)
 ;          (|import|         |compImport|)
-          (|is|             |compIs|)
+;          (|is|             |compIs|)
           (|Join|           |compJoin|)
 ;          (|+->|            |compLambda|)
           (|leave|          |compLeave|)