een defined. An ambiguous symbol will have the symbol
        definition on the left, followed by an equals '=' and a list of
        core symbols on the right.</p>
        <p>For example you can defined the symbol 'N' to represent 'A', 'C', 'G'
        or 'T' as follows:</p>
        <div class="example">
          N = ACGT
        </div>
        <p>If there is a <b>single</b> core symbol on the right of
	an ambiguous symbol definition, the symbol is considered to be an <b>alias</b>
	for the core symbol on 