angent of a C4.
        </li>
        <li>
          <b>C4_ATANH</b> evaluates the inverse hyperbolic tangent of a C4.
        </li>
        <li>
          <b>C4_CONJ</b> evaluates the conjugate of a C4.
        </li>
        <li>
          <b>C4_COPY</b> copies a C4.
        </li>
        <li>
          <b>C4_COS</b> evaluates the cosine of a C4.
        </li>
        <li>
          <b>C4_COSH</b> evaluates the hyperbolic cosine of a C4.
        </li>
        <li>
          <b>C4_CUBE_ROOT</b> returns the 