code: @XmlElementDecl(namespace = "http://www.w3.org/1998/Math/MathML", name = "matrix")
      public JAXBElement<MatrixType> createMatrix(MatrixType value) {
          return new JAXBElement<MatrixType>(_Matrix_QNAME, MatrixType.class, null, value);
      }
docs: Create an instance of {@link JAXBElement }{@code <}{@link MatrixType }{@code >}}