一个地区有若干家商店销售某种品牌的真空吸尘器。(1)假如所有销售商要价相同，他们的长期经济利

一个地区有若干家商店销售某种品牌的真空吸尘器。

(1)假如所有销售商要价相同，他们的长期经济利润是否都等于零？

(2)假如所有销售商要价相同，但是一家当地销售商的商店经营场所为他自己拥有的房子，不必付租金，这个销售商的经济利润为正吗？

(3)不必付租金的这家销售商是否有激励去降低其销售价格？

A certain brand of vacuum cleaners can be purchased from several local stores as well as from several catalogue or website sources.

a If all sellers charge the same price for the vacuum cleaner, will they all earn zero economic profit in the long run？

b. If all sellers charge the same price and one local seller owns the building in which he does business, paying no rent, is this seller earning a position economic profit？

e. Does the seller who pays no rent have an incentive to lower the price he charges for the vacuum cleaner？