The modern literature on city formation and development, for example the New Economic Geography literature, has studied the agglomeration of agents in size or mass. We investigate agglomeration in sorting or by type of worker, that implies agglomeration in size when worker populations differ by...

Credit contracting between a lender with a market power and a small start-up entrepreneur may lead to a rejection of projects whose expected benefits are higher than their total costs when an adverse selection is present. This inefficiency may be eliminated by a government support in the form of...