, but is opposite to the usual
          mathematical conventions.
        </p>
<p>
          Some other sources include an additional Condon-Shortley phase term of
          (-1)<sup>m</sup> in the definition of this function: note however that our definition
          of the associated Legendre polynomial already includes this term.
        </p>
<p>
          This implementation returns zero for m &gt; n
        </p>
<p>
          For &#952; &#160; outside [0, &#960;] and &#966; &#160; outside [0, 2&#960;