This page is an essay on Wikipedia:Deletion policy.
|This page in a nutshell: Calling an editor a liar is not a valid argument in AfD discussions (or anywhere else, for that matter).|
Simply calling another editor a "liar" (which is a personal attack) or even stating that the editor is incorrect is not a reason to keep or delete any article on Wikipedia. If the editor is incorrectly quoting, misapplying information, misinterpreting data, or otherwise simply misinformed, a useful response is to provide a reference to the correct information.
If an editor makes a statement and holds it out as a fact without proper sourcing, it is more than fair to ask for sources. At the same time, it is best to always assume good faith among your fellow editors.