で、あるか

Is that so.
This is a phrase used by Nobunaga in a story recounted by Ōta Gyūichi in the Shinchō Kōki (Nobunaga Chronicles). According to the story, when a retainer of the famous warlord Saitō Dōsan Introduced Saitō (who had already retreated into monkhood at the time) to Nobunaga, Nobunaga, leaning on a pillar, responded with a simple "is that so", dismissing the great man.