Brian Steinberg Senior TV Editor A judge overseeing a much-scrutinized defamation trial brought by Dominion Voting Systems against Fox News and its corporate parent has admonished attorneys for the media company several times this week in preliminary hearings and suggested Wednesday he may appoint an outside monitor to ensure Fox isn’t withholding evidence. Judge Eric M. David of Delaware’s Superior Court suggested Wednesday that he might appoint a special master to probe whether Fox lied about withholding evidence after Dominion attorneys made a presentation about materials not given to them in the discovery process that they believe are warranted. There were also claims made that Fox Corp. declined to acknowledge that Rupert Murdoch, executive chairman of Fox Corp., was also an officer of Fox News — a detail that would affect what kinds of materials Dominion could obtain.