diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -81,3 +81,6 @@
 
 * Fifth version revised B. Fixed inlining policies so that ghc -dcore-lint produces now no warnings. Some minor code improvements.
 
+## 0.5.3.0 -- 2020-11-12
+
+* Fifth version revised C. Fixed issues with empty second element in the tuple for maximumElBy function.
diff --git a/Languages/UniquenessPeriods/Vector/General/Debug.hs b/Languages/UniquenessPeriods/Vector/General/Debug.hs
--- a/Languages/UniquenessPeriods/Vector/General/Debug.hs
+++ b/Languages/UniquenessPeriods/Vector/General/Debug.hs
@@ -56,6 +56,7 @@
   ->  UniqG2 a b -- ^ The data to be analyzed.
   -> UniquenessG1 a b -- ^ The maximum element in respect with the given parameters.
 maximumElBy k vN y
+ | V.null . snd .get22 $ y = error "Languages.UniquenessPeriods.Vector.General.Debug.maximumElBy: undefined for the empty second element in the tuple. "
  | compare k (V.length vN) == GT = error "Languages.UniquenessPeriods.Vector.General.Debug.maximumElBy: undefined for that amount of norms. "
  | compare k 0 == GT =
    let !maxK = V.maximumBy (\(_,vN0,_) (_,vN1,_) -> compare (V.unsafeIndex vN0 (k - 1)) (V.unsafeIndex vN1 (k - 1))) . snd . get22 $ y
@@ -212,7 +213,9 @@
   -> V.Vector ([b] -> b) -- ^ 'V.Vector' of the represented as functions \"properties\" to be applied consequently.
   -> UniqG2 a b -- ^ The data to be analyzed.
   -> UniqG2 a b
-maximumElByVec k vN x = let !uniq = maximumElBy k vN x in let !snD = secondFrom3 uniq in UL2 ((\(!v1,!v2) -> ((fst . get22 $ x) ++ V.toList v1,v2)) .
+maximumElByVec k vN x
+ | V.null . snd . get22 $ x = x
+ | otherwise = let !uniq = maximumElBy k vN x in let !snD = secondFrom3 uniq in UL2 ((\(!v1,!v2) -> ((fst . get22 $ x) ++ V.toList v1,v2)) .
       V.unstablePartition (equalSnDs snD . secondFrom3) . snd . get22 $ x)
 {-# INLINE maximumElByVec #-}
 
diff --git a/uniqueness-periods-vector-general.cabal b/uniqueness-periods-vector-general.cabal
--- a/uniqueness-periods-vector-general.cabal
+++ b/uniqueness-periods-vector-general.cabal
@@ -2,7 +2,7 @@
 --   For further documentation, see http://haskell.org/cabal/users-guide/
 
 name:                uniqueness-periods-vector-general
-version:             0.5.2.0
+version:             0.5.3.0
 synopsis:            Some kind of the optimization approach to data inner structure.
 description:         Generalization of the functionality of the dobutokO-poetry-general-languages package
 homepage:            https://hackage.haskell.org/package/uniqueness-periods-vector-general