diff --git a/comfort-blas.cabal b/comfort-blas.cabal
--- a/comfort-blas.cabal
+++ b/comfort-blas.cabal
@@ -1,6 +1,6 @@
 Cabal-Version:    2.2
 Name:             comfort-blas
-Version:          0.0.3
+Version:          0.0.3.1
 License:          BSD-3-Clause
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
@@ -17,7 +17,7 @@
   Makefile
 
 Source-Repository this
-  Tag:         0.0.3
+  Tag:         0.0.3.1
   Type:        darcs
   Location:    https://hub.darcs.net/thielema/comfort-blas/
 
@@ -35,7 +35,7 @@
     non-empty >=0.3.1 && <0.4,
     containers >=0.4 && <0.8,
     semigroups >=0.19 && <0.21,
-    deepseq >=1.3 && <1.6,
+    deepseq >=1.3 && <1.7,
     transformers >=0.4 && <0.7,
     utility-ht >=0.0.13 && <0.1,
     base >=4.5 && <5
diff --git a/src/Numeric/BLAS/Slice.hs b/src/Numeric/BLAS/Slice.hs
--- a/src/Numeric/BLAS/Slice.hs
+++ b/src/Numeric/BLAS/Slice.hs
@@ -101,6 +101,20 @@
       List.take (Shape.size sh1) $ iterate (k+) s
 
 
+{- |
+prop> :{
+   QC.forAll (QC.choose (1,100)) $ \numTopRows ->
+   QC.forAll (QC.choose (1,100)) $ \numBottomRows ->
+   QC.forAll (QC.choose (0,100)) $ \numColumns ->
+   QC.forAll (genSlice (shapeInt numTopRows ::+ shapeInt numBottomRows,
+                        shapeInt numColumns)) $ \slice ->
+   Slice.rowArray slice
+   ==
+   Array.append
+      (Slice.rowArray (Slice.topSubmatrix slice))
+      (Slice.rowArray (Slice.bottomSubmatrix slice))
+:}
+-}
 topSubmatrix ::
    (Shape.C sh, Shape.C sh0, Shape.C sh1) =>
    T (sh0::+sh1, sh) -> T (sh0,sh)
@@ -111,7 +125,7 @@
    (Shape.C sh, Shape.C sh0, Shape.C sh1) =>
    T (sh0::+sh1, sh) -> T (sh1,sh)
 bottomSubmatrix (Cons s k (sh0::+sh1, sh)) =
-   Cons (s + k * Shape.size sh0) k (sh1,sh)
+   Cons (s + k * Shape.size (sh0,sh)) k (sh1,sh)
 
 
 diagonal :: (Shape.C sh) => T (Shape.Square sh) -> T sh
diff --git a/test/Test/Numeric/BLAS/Slice.hs b/test/Test/Numeric/BLAS/Slice.hs
--- a/test/Test/Numeric/BLAS/Slice.hs
+++ b/test/Test/Numeric/BLAS/Slice.hs
@@ -62,33 +62,49 @@
 {-# LINE 92 "src/Numeric/BLAS/Slice.hs" #-}
       QC.forAll (QC.choose (0,100)) $ \numRows -> QC.forAll (QC.choose (1,100)) $ \numColumns -> QC.forAll (genSlice (shapeInt numRows, shapeInt numColumns)) $ \slice -> QC.forAll (QC.elements $ Shape.indices $ shapeInt numColumns) $ \ix -> Slice.column ix slice == Slice.columnArray slice ! ix
   )
- DocTest.printPrefix "Numeric.BLAS.Slice:173: "
-{-# LINE 173 "src/Numeric/BLAS/Slice.hs" #-}
+ DocTest.printPrefix "Numeric.BLAS.Slice:105: "
+{-# LINE 105 "src/Numeric/BLAS/Slice.hs" #-}
  DocTest.property(
-{-# LINE 173 "src/Numeric/BLAS/Slice.hs" #-}
+{-# LINE 105 "src/Numeric/BLAS/Slice.hs" #-}
+        
+   QC.forAll (QC.choose (1,100)) $ \numTopRows ->
+   QC.forAll (QC.choose (1,100)) $ \numBottomRows ->
+   QC.forAll (QC.choose (0,100)) $ \numColumns ->
+   QC.forAll (genSlice (shapeInt numTopRows ::+ shapeInt numBottomRows,
+                        shapeInt numColumns)) $ \slice ->
+   Slice.rowArray slice
+   ==
+   Array.append
+      (Slice.rowArray (Slice.topSubmatrix slice))
+      (Slice.rowArray (Slice.bottomSubmatrix slice))
+  )
+ DocTest.printPrefix "Numeric.BLAS.Slice:187: "
+{-# LINE 187 "src/Numeric/BLAS/Slice.hs" #-}
+ DocTest.property(
+{-# LINE 187 "src/Numeric/BLAS/Slice.hs" #-}
       QC.forAll (genSlice =<< genAppend) $ \slice -> Slice.take (case Slice.shape slice of (sh::+_) -> Shape.size sh) (toShapeInt slice) == toShapeInt (Slice.left slice)
   )
- DocTest.printPrefix "Numeric.BLAS.Slice:182: "
-{-# LINE 182 "src/Numeric/BLAS/Slice.hs" #-}
+ DocTest.printPrefix "Numeric.BLAS.Slice:196: "
+{-# LINE 196 "src/Numeric/BLAS/Slice.hs" #-}
  DocTest.property(
-{-# LINE 182 "src/Numeric/BLAS/Slice.hs" #-}
+{-# LINE 196 "src/Numeric/BLAS/Slice.hs" #-}
       QC.forAll (genSlice =<< genAppend) $ \slice -> Slice.drop (case Slice.shape slice of (sh::+_) -> Shape.size sh) (toShapeInt slice) == toShapeInt (Slice.right slice)
   )
- DocTest.printPrefix "Numeric.BLAS.Slice:193: "
-{-# LINE 193 "src/Numeric/BLAS/Slice.hs" #-}
+ DocTest.printPrefix "Numeric.BLAS.Slice:207: "
+{-# LINE 207 "src/Numeric/BLAS/Slice.hs" #-}
  DocTest.property(
-{-# LINE 193 "src/Numeric/BLAS/Slice.hs" #-}
+{-# LINE 207 "src/Numeric/BLAS/Slice.hs" #-}
       \(QC.NonNegative n) -> QC.forAll (genSlice $ shapeInt n) $ \slice (QC.NonNegative start) (QC.NonNegative size) -> Slice.sub start size slice == Slice.take size (Slice.drop start slice)
   )
- DocTest.printPrefix "Numeric.BLAS.Slice:203: "
-{-# LINE 203 "src/Numeric/BLAS/Slice.hs" #-}
+ DocTest.printPrefix "Numeric.BLAS.Slice:217: "
+{-# LINE 217 "src/Numeric/BLAS/Slice.hs" #-}
  DocTest.property(
-{-# LINE 203 "src/Numeric/BLAS/Slice.hs" #-}
+{-# LINE 217 "src/Numeric/BLAS/Slice.hs" #-}
       QC.forAll (fmap shapeInt $ QC.choose (0,100)) $ \shapeA -> QC.forAll (fmap shapeInt $ QC.choose (0,100)) $ \shapeB -> QC.forAll (fmap shapeInt $ QC.choose (0,100)) $ \shapeC -> QC.forAll (genSlice2 (Map.fromList $ ('a', shapeA) : ('b', shapeB) : ('c', shapeC) : []) (shapeA ::+ shapeB ::+ shapeC)) $ \(sliceMap, sliceParted) -> Slice.map sliceMap Map.! 'b' == Slice.left (Slice.right sliceParted)
   )
- DocTest.printPrefix "Numeric.BLAS.Slice:205: "
-{-# LINE 205 "src/Numeric/BLAS/Slice.hs" #-}
+ DocTest.printPrefix "Numeric.BLAS.Slice:219: "
+{-# LINE 219 "src/Numeric/BLAS/Slice.hs" #-}
  DocTest.property(
-{-# LINE 205 "src/Numeric/BLAS/Slice.hs" #-}
+{-# LINE 219 "src/Numeric/BLAS/Slice.hs" #-}
       QC.forAll (QC.choose (0,100)) $ \numRows -> QC.forAll (QC.choose (0,100)) $ \numColumns -> let rowShape = shapeInt numRows; columnShape = shapeInt numColumns; mapShape_ = Map.fromList $ map (\k -> (k, columnShape)) (Shape.indices rowShape) in QC.forAll (genSlice2 mapShape_ (rowShape, columnShape)) $ \(sliceMap, sliceMatrix) -> Map.toAscList (Slice.map sliceMap) == Array.toAssociations (Slice.rowArray sliceMatrix)
   )