diff --git a/src/function/set/setCartesian.js b/src/function/set/setCartesian.js
index bc9db7c26..55eeb3f1f 100644
--- a/src/function/set/setCartesian.js
+++ b/src/function/set/setCartesian.js
@@ -3,7 +3,7 @@
 const flatten = require('../../utils/array').flatten
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const matrix = load(require('../../type/matrix/DenseMatrix'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
@@ -33,7 +33,7 @@ function factory (type, config, load, typed) {
     'Array | Matrix, Array | Matrix': function (a1, a2) {
       let result = []
 
-      if (subset(size(a1), new index(0)) !== 0 && subset(size(a2), new index(0)) !== 0) { // if any of them is empty, return empty
+      if (subset(size(a1), new MatrixIndex(0)) !== 0 && subset(size(a2), new MatrixIndex(0)) !== 0) { // if any of them is empty, return empty
         const b1 = flatten(Array.isArray(a1) ? a1 : a1.toArray()).sort(compareNatural)
         const b2 = flatten(Array.isArray(a2) ? a2 : a2.toArray()).sort(compareNatural)
         result = []
diff --git a/src/function/set/setDifference.js b/src/function/set/setDifference.js
index ad5c5cf02..3eefd3124 100644
--- a/src/function/set/setDifference.js
+++ b/src/function/set/setDifference.js
@@ -5,7 +5,7 @@ const identify = require('../../utils/array').identify
 const generalize = require('../../utils/array').generalize
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const matrix = load(require('../../type/matrix/DenseMatrix'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
@@ -35,9 +35,9 @@ function factory (type, config, load, typed) {
   const setDifference = typed('setDifference', {
     'Array | Matrix, Array | Matrix': function (a1, a2) {
       let result
-      if (subset(size(a1), new index(0)) === 0) { // empty-anything=empty
+      if (subset(size(a1), new MatrixIndex(0)) === 0) { // empty-anything=empty
         result = []
-      } else if (subset(size(a2), new index(0)) === 0) { // anything-empty=anything
+      } else if (subset(size(a2), new MatrixIndex(0)) === 0) { // anything-empty=anything
         return flatten(a1.toArray())
       } else {
         const b1 = identify(flatten(Array.isArray(a1) ? a1 : a1.toArray()).sort(compareNatural))
diff --git a/src/function/set/setDistinct.js b/src/function/set/setDistinct.js
index bb7ab3cf5..50576efbf 100644
--- a/src/function/set/setDistinct.js
+++ b/src/function/set/setDistinct.js
@@ -3,7 +3,7 @@
 const flatten = require('../../utils/array').flatten
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const matrix = load(require('../../type/matrix/DenseMatrix'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
@@ -31,7 +31,7 @@ function factory (type, config, load, typed) {
   const setDistinct = typed('setDistinct', {
     'Array | Matrix': function (a) {
       let result
-      if (subset(size(a), new index(0)) === 0) { // if empty, return empty
+      if (subset(size(a), new MatrixIndex(0)) === 0) { // if empty, return empty
         result = []
       } else {
         const b = flatten(Array.isArray(a) ? a : a.toArray()).sort(compareNatural)
diff --git a/src/function/set/setIntersect.js b/src/function/set/setIntersect.js
index fc812859c..3d8ed3c57 100644
--- a/src/function/set/setIntersect.js
+++ b/src/function/set/setIntersect.js
@@ -5,7 +5,7 @@ const identify = require('../../utils/array').identify
 const generalize = require('../../utils/array').generalize
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const matrix = load(require('../../type/matrix/DenseMatrix'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
@@ -35,7 +35,7 @@ function factory (type, config, load, typed) {
   const setIntersect = typed('setIntersect', {
     'Array | Matrix, Array | Matrix': function (a1, a2) {
       let result
-      if (subset(size(a1), new index(0)) === 0 || subset(size(a2), new index(0)) === 0) { // of any of them is empty, return empty
+      if (subset(size(a1), new MatrixIndex(0)) === 0 || subset(size(a2), new MatrixIndex(0)) === 0) { // of any of them is empty, return empty
         result = []
       } else {
         const b1 = identify(flatten(Array.isArray(a1) ? a1 : a1.toArray()).sort(compareNatural))
diff --git a/src/function/set/setIsSubset.js b/src/function/set/setIsSubset.js
index 4223d0806..2619808a2 100644
--- a/src/function/set/setIsSubset.js
+++ b/src/function/set/setIsSubset.js
@@ -4,7 +4,7 @@ const flatten = require('../../utils/array').flatten
 const identify = require('../../utils/array').identify
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
   const compareNatural = load(require('../relational/compareNatural'))
@@ -32,9 +32,9 @@ function factory (type, config, load, typed) {
    */
   const setIsSubset = typed('setIsSubset', {
     'Array | Matrix, Array | Matrix': function (a1, a2) {
-      if (subset(size(a1), new index(0)) === 0) { // empty is a subset of anything
+      if (subset(size(a1), new MatrixIndex(0)) === 0) { // empty is a subset of anything
         return true
-      } else if (subset(size(a2), new index(0)) === 0) { // anything is not a subset of empty
+      } else if (subset(size(a2), new MatrixIndex(0)) === 0) { // anything is not a subset of empty
         return false
       }
       const b1 = identify(flatten(Array.isArray(a1) ? a1 : a1.toArray()).sort(compareNatural))
diff --git a/src/function/set/setMultiplicity.js b/src/function/set/setMultiplicity.js
index 19fc4e83f..b48589340 100644
--- a/src/function/set/setMultiplicity.js
+++ b/src/function/set/setMultiplicity.js
@@ -4,7 +4,7 @@ const flatten = require('../../utils/array').flatten
 
 function factory (type, config, load, typed) {
   const compareNatural = load(require('../relational/compareNatural'))
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
 
@@ -31,7 +31,7 @@ function factory (type, config, load, typed) {
    */
   const setMultiplicity = typed('setMultiplicity', {
     'number | BigNumber | Fraction | Complex, Array | Matrix': function (e, a) {
-      if (subset(size(a), new index(0)) === 0) { // if empty, return 0
+      if (subset(size(a), new MatrixIndex(0)) === 0) { // if empty, return 0
         return 0
       }
       const b = flatten(Array.isArray(a) ? a : a.toArray())
diff --git a/src/function/set/setPowerset.js b/src/function/set/setPowerset.js
index 3421f9cb6..e43874bf2 100644
--- a/src/function/set/setPowerset.js
+++ b/src/function/set/setPowerset.js
@@ -3,7 +3,7 @@
 const flatten = require('../../utils/array').flatten
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
   const compareNatural = load(require('../relational/compareNatural'))
@@ -29,7 +29,7 @@ function factory (type, config, load, typed) {
    */
   const setPowerset = typed('setPowerset', {
     'Array | Matrix': function (a) {
-      if (subset(size(a), new index(0)) === 0) { // if empty, return empty
+      if (subset(size(a), new MatrixIndex(0)) === 0) { // if empty, return empty
         return []
       }
       const b = flatten(Array.isArray(a) ? a : a.toArray()).sort(compareNatural)
diff --git a/src/function/set/setSymDifference.js b/src/function/set/setSymDifference.js
index 256d4d03d..3aae2b602 100644
--- a/src/function/set/setSymDifference.js
+++ b/src/function/set/setSymDifference.js
@@ -3,7 +3,7 @@
 const flatten = require('../../utils/array').flatten
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const concat = load(require('../matrix/concat'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
@@ -32,9 +32,9 @@ function factory (type, config, load, typed) {
    */
   const setSymDifference = typed('setSymDifference', {
     'Array | Matrix, Array | Matrix': function (a1, a2) {
-      if (subset(size(a1), new index(0)) === 0) { // if any of them is empty, return the other one
+      if (subset(size(a1), new MatrixIndex(0)) === 0) { // if any of them is empty, return the other one
         return flatten(a2)
-      } else if (subset(size(a2), new index(0)) === 0) {
+      } else if (subset(size(a2), new MatrixIndex(0)) === 0) {
         return flatten(a1)
       }
       const b1 = flatten(a1)
diff --git a/src/function/set/setUnion.js b/src/function/set/setUnion.js
index eb7be7c73..1c89ba555 100644
--- a/src/function/set/setUnion.js
+++ b/src/function/set/setUnion.js
@@ -3,7 +3,7 @@
 const flatten = require('../../utils/array').flatten
 
 function factory (type, config, load, typed) {
-  const index = load(require('../../type/matrix/MatrixIndex'))
+  const MatrixIndex = load(require('../../type/matrix/MatrixIndex'))
   const concat = load(require('../matrix/concat'))
   const size = load(require('../matrix/size'))
   const subset = load(require('../matrix/subset'))
@@ -33,9 +33,9 @@ function factory (type, config, load, typed) {
    */
   const setUnion = typed('setUnion', {
     'Array | Matrix, Array | Matrix': function (a1, a2) {
-      if (subset(size(a1), new index(0)) === 0) { // if any of them is empty, return the other one
+      if (subset(size(a1), new MatrixIndex(0)) === 0) { // if any of them is empty, return the other one
         return flatten(a2)
-      } else if (subset(size(a2), new index(0)) === 0) {
+      } else if (subset(size(a2), new MatrixIndex(0)) === 0) {
         return flatten(a1)
       }
       const b1 = flatten(a1)