Add negation for dense termlists

2_78.rkt

@@ -659,6 +659,8 @@
                    (zero-pad
                     (- (order term) 1)
                     term-list))))))
+  (define (negate terms)
+    (map - terms))
 
   (define (tag l) (attach-tag 'dense l))
 
@@ -685,6 +687,11 @@
 
   (put 'empty-termlist? '(dense)
        empty-termlist?)
+
+  ;; Operators
+  (put 'negate '(dense)
+       (lambda (termlist)
+         (tag (negate termlist))))
   
   'done)