Avoid introducing a sum when negating a product.

diff --git a/LTA/Symbolic.hs b/LTA/Symbolic.hs
index d05f5f6c36399785fc16fc2821de176ed7a03a5e..b52cfc7bc8038a72b33307c5f22a74b6226dec86 100644 (file)
--- a/LTA/Symbolic.hs
+++ b/LTA/Symbolic.hs
@@ -187,6 +187,7 @@ instance Num Expr where
   (*) a b = simplify . Product $ empty `addPair` (a, 1) `addPair` (b, 1)
   abs = UnaryFunction Abs
   fromInteger = Literal . fromInteger
+  negate (Product pairSeq) = Product $ transformOverall pairSeq (* (-1))
   negate a = simplify . Sum $ empty `addPair` (a, -1)
   signum = UnaryFunction Signum