The judge who will decide whether Google holds a monopoly over technology that matches buyers and sellers of online advertising must choose whether to believe what Google executives wrote or what they have said on the witness stand.

In an effort to quell monopoly concerns in the EU, Google reportedly offered to sell its AdX advertising marketplace. Sources told Reuters that European publishers rejected Google's offer, arguing that the company would have to divest more in order to dismantle the conflicts of interest in its online advertising operations.

Google this year offered to sell its advertising marketplace Ad Exchange, or AdX, to end an EU antitrust investigation. But European publishers rejected the proposal, Reuters reported this week . The news agency cited two people with knowledge of the matter but did not name them.