diff --git a/Algorithm/Graph/MarkovChain.php b/Algorithm/Graph/MarkovChain.php
index c74eb26ac..ea74bc960 100644
--- a/Algorithm/Graph/MarkovChain.php
+++ b/Algorithm/Graph/MarkovChain.php
@@ -137,7 +137,7 @@ final class MarkovChain
                 $cProb += $p;
 
                 if ($prob <= $cProb) {
-                    $new   = $val;
+                    $new = $val;
 
                     break;
                 }
@@ -177,7 +177,7 @@ final class MarkovChain
 
         $prob = 1.0;
         for ($i = $this->order; $i < $length; ++$i) {
-            $prob *= $this->data[\implode($key)][$path[$i]] ?? 0.0;
+            $prob *= $this->data[\implode(' ', $key)][$path[$i]] ?? 0.0;
 
             $key[] = $path[$i];
             \array_shift($key);
diff --git a/DataStorage/Database/Mapper/ReadMapper.php b/DataStorage/Database/Mapper/ReadMapper.php
index 7d696467d..ca4a3650f 100755
--- a/DataStorage/Database/Mapper/ReadMapper.php
+++ b/DataStorage/Database/Mapper/ReadMapper.php
@@ -433,7 +433,7 @@ final class ReadMapper extends DataMapperAbstract
         $query = $this->getQuery(
             null,
             [
-                'COUNT(' . (empty($this->columns) ? '*' : \implode($this->columns)) . ')' => 'count'
+                'COUNT(' . (empty($this->columns) ? '*' : \implode(',', $this->columns)) . ')' => 'count',
             ]
         );
 
@@ -452,7 +452,7 @@ final class ReadMapper extends DataMapperAbstract
         $query = $this->getQuery(
             null,
             [
-                'SUM(' . (empty($this->columns) ? '*' : \implode($this->columns)) . ')' => 'sum'
+                'SUM(' . (empty($this->columns) ? '*' : \implode(',', $this->columns)) . ')' => 'sum',
             ]
         );
 
diff --git a/Math/Geometry/ConvexHull/GrahamScan.php b/Math/Geometry/ConvexHull/GrahamScan.php
index 440d5cc60..a9f566c69 100644
--- a/Math/Geometry/ConvexHull/GrahamScan.php
+++ b/Math/Geometry/ConvexHull/GrahamScan.php
@@ -70,7 +70,7 @@ final class GrahamScan
         $subpoints = \array_slice($points, 2, $count);
         \usort($subpoints, function (array $a, array $b) use ($c) : int {
             // @todo: Might be wrong order of comparison
-            return \atan2($a['y'] - $c['y'], $a['x'] - $c['x']) <=> \atan2( $b['y'] -  $c['y'],  $b['x'] - $c['x']);
+            return \atan2($a['y'] - $c['y'], $a['x'] - $c['x']) <=> \atan2($b['y'] - $c['y'],  $b['x'] - $c['x']);
         });
 
         /** @var array<int, array{x:int|float, y:int|float}> $points */
@@ -106,9 +106,9 @@ final class GrahamScan
     /**
      * Counterclockwise rotation
      *
-     * @param array<x:int|float, y:int|float> $a Vector
-     * @param array<x:int|float, y:int|float> $b Vector
-     * @param array<x:int|float, y:int|float> $c Vector
+     * @param array{x:int|float, y:int|float} $a Vector
+     * @param array{x:int|float, y:int|float} $b Vector
+     * @param array{x:int|float, y:int|float} $c Vector
      *
      * @return int|float
      *
diff --git a/Math/Optimization/Simplex.php b/Math/Optimization/Simplex.php
index 190f28a48..1a46ef507 100644
--- a/Math/Optimization/Simplex.php
+++ b/Math/Optimization/Simplex.php
@@ -26,6 +26,7 @@ namespace phpOMS\Math\Optimization;
 class Simplex
 {
     private int $m = 0;
+
     private int $n = 0;
 
     private array $A = [];
@@ -40,7 +41,7 @@ class Simplex
 
     private array $Nonbasic = [];
 
-    private function pivot (int $x, int $y)
+    private function pivot (int $x, int $y) : void
     {
         for ($j = 0; $j < $this->n; ++$j) {
             if ($j !== $y) {
@@ -73,20 +74,20 @@ class Simplex
         $this->v += $this->c[$y] * $this->b[$x];
         $this->c[$y] *= $this->A[$x][$y];
 
-        $temp = $this->Basic[$x];
-        $this->Basic[$x] = $this->Nonbasic[$y];
+        $temp               = $this->Basic[$x];
+        $this->Basic[$x]    = $this->Nonbasic[$y];
         $this->Nonbasic[$y] = $temp;
     }
 
     private function iterate() : int
     {
-        $ind = -1;
+        $ind  = -1;
         $best = -1;
 
         for ($j = 0; $j < $this->n; ++$j) {
             if ($this->c[$j] > 0) {
                 if ($best === -1 || $this->Nonbasic[$j] < $ind) {
-                    $ind = $this->Nonbasic[$j];
+                    $ind  = $this->Nonbasic[$j];
                     $best = $j;
                 }
             }
@@ -96,14 +97,14 @@ class Simplex
             return 1;
         }
 
-        $maxConstraint = \INF;
+        $maxConstraint  = \INF;
         $bestConstraint = -1;
 
         for ($i = 0; $i < $this->m; ++$i) {
             if ($this->A[$i][$best] < 0) {
                 $currentConstraint = -$this->b[$i] / $this->A[$i][$best];
                 if ($currentConstraint < $maxConstraint) {
-                    $maxConstraint = $currentConstraint;
+                    $maxConstraint  = $currentConstraint;
                     $bestConstraint = $i;
                 }
             }
@@ -120,12 +121,12 @@ class Simplex
 
     private function initialize() : int
     {
-        $k = -1;
+        $k    = -1;
         $minB = -1;
 
         for ($i = 0; $i < $this->m; ++$i) {
             if ($k === -1 || $this->b[$i] < $minB) {
-                $k = $i;
+                $k    = $i;
                 $minB = $this->b[$i];
             }
         }
@@ -201,8 +202,8 @@ class Simplex
             $this->A[$i][$nonbasicZ] = $this->A[$i][$this->n - 1];
         }
 
-        $temp = $this->Nonbasic[$nonbasicZ];
-        $this->Nonbasic[$nonbasicZ] = $this->Nonbasic[$this->n - 1];
+        $temp                         = $this->Nonbasic[$nonbasicZ];
+        $this->Nonbasic[$nonbasicZ]   = $this->Nonbasic[$this->n - 1];
         $this->Nonbasic[$this->n - 1] = $temp;
 
         --$this->n;
diff --git a/Stdlib/Tree/BinarySearchTree.php b/Stdlib/Tree/BinarySearchTree.php
index 7b336f8b8..044e217c2 100644
--- a/Stdlib/Tree/BinarySearchTree.php
+++ b/Stdlib/Tree/BinarySearchTree.php
@@ -185,7 +185,7 @@ class BinarySearchTree
 
             if ($comparison < 0) {
                 if ($current->left === null) {
-                    $BST         = new BinarySearchTree();
+                    $BST         = new self();
                     $new         = new Node($node->key, $node->data);
                     $new->parent = $current;
                     $new->tree   = $BST;
@@ -197,7 +197,7 @@ class BinarySearchTree
                 }
             } elseif ($comparison > 0) {
                 if ($current->right === null) {
-                    $BST         = new BinarySearchTree();
+                    $BST         = new self();
                     $new         = new Node($node->key, $node->data);
                     $new->parent = $current;
                     $new->tree   = $BST;
diff --git a/tests/Utils/IO/Spreadsheet/SpreadsheetDatabaseMapperTest.php b/tests/Utils/IO/Spreadsheet/SpreadsheetDatabaseMapperTest.php
index b30db62f7..032ed1ab9 100755
--- a/tests/Utils/IO/Spreadsheet/SpreadsheetDatabaseMapperTest.php
+++ b/tests/Utils/IO/Spreadsheet/SpreadsheetDatabaseMapperTest.php
@@ -14,9 +14,9 @@ declare(strict_types=1);
 
 namespace phpOMS\tests\Utils\IO\Spreadsheet;
 
-use phpOMS\tests\Autoloader;
 use phpOMS\DataStorage\Database\Connection\SQLiteConnection;
 use phpOMS\DataStorage\Database\Query\Builder;
+use phpOMS\tests\Autoloader;
 use phpOMS\Utils\IO\Spreadsheet\SpreadsheetDatabaseMapper;
 use phpOMS\Utils\StringUtils;