diff --git a/externs/olx.js b/externs/olx.js
index 5e0d75e784..5babe3e053 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -6850,7 +6850,7 @@ olx.view.FitGeometryOptions.prototype.maxZoom;
 /**
  * @typedef {{animate: boolean,
  *     attributions: Object.<string, ol.Attribution>,
- *     coordinateToPixelMatrix: goog.vec.Mat4.Number,
+ *     coordinateToPixelMatrix: ol.vec.Mat4.Number,
  *     extent: (null|ol.Extent),
  *     focus: ol.Coordinate,
  *     index: number,
@@ -6858,7 +6858,7 @@ olx.view.FitGeometryOptions.prototype.maxZoom;
  *     layerStatesArray: Array.<ol.layer.LayerState>,
  *     logos: Object.<string, string>,
  *     pixelRatio: number,
- *     pixelToCoordinateMatrix: goog.vec.Mat4.Number,
+ *     pixelToCoordinateMatrix: ol.vec.Mat4.Number,
  *     postRenderFunctions: Array.<ol.PostRenderFunction>,
  *     size: ol.Size,
  *     skippedFeatureUids: Object.<string, boolean>,
diff --git a/src/ol/vec/mat4.js b/src/ol/vec/mat4.js
index 54e7df7e71..4fa6f5ca77 100644
--- a/src/ol/vec/mat4.js
+++ b/src/ol/vec/mat4.js
@@ -1,8 +1,16 @@
 goog.provide('ol.vec.Mat4');
+goog.provide('ol.vec.Mat4.Number');
 
 goog.require('goog.vec.Mat4');
 
 
+/**
+ * A alias for the goog.vec.Number type.
+ * @typedef {goog.vec.Number}
+ */
+ol.vec.Mat4.Number;
+
+
 /**
  * @param {!goog.vec.Mat4.Number} mat Matrix.
  * @param {number} translateX1 Translate X1.