Forum:"Ask" Wikitext and NOT operators

Hello. I've been trying to use Wikitext in some Tips articles, and more than ofter I've needed to use a NOT operator. For example, to make an #ask command in Card Tips:Chronomaly Mayan Machine, the "Summon" category of the card should be different than "Cannot Normal Summon", but I can't find a way to use a NOT operator like that, as usual NOT operators like "!" and "<>" don't seem to work. Is there any way to script that in Wikitext? Also, still a question about Wikitext, is there any way to check if a value is null?

Thank you for your time. GMTails (talk • contribs) 03:24, November 13, 2013 (UTC).