Clearly it doesn&#x27;t happen often; but if someone makes a significant contribution to a paper the length of time it took to produce is irrelevant.<p>It has happened before to non-number-people (e.g. <a href="http:&#x2F;&#x2F;www.anoleannals.org&#x2F;2012&#x2F;01&#x2F;03&#x2F;posthumous-co-authorship-what-are-the-rules&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.anoleannals.org&#x2F;2012&#x2F;01&#x2F;03&#x2F;posthumous-co-authorsh...</a>), and it doesn&#x27;t seem like someone added Erdős&#x27; name inappropriately..