please answer

Q4. Suppose that the seller allocates m (2 2) units of a homogeneous good via an auction. There are n potential buyers (N = (1, ...,n),n 2 m+1), and each buyer can purchase at most one unit. The reservation value for buyer i e N to the good is v;. Consider a following "(m + 1)-th price auction." Each bidder simultaneously submits a bid b, e R+ The bidders with the m highest bids win a unit. Each winner pays the (m + 1)-th highest bid. Show that it is a weakly dominant strategy for each bidder i to submit s; (v;) = vi