I've never heard of monotonic being used for two (input) variables, but I suppose it would mean that, for each fixed value of y, u is a monotonic function of x, and for each fixed value of x, u is a monotonic function of y (and I expect they'd need to be either both monotonic increasing or both monotonic decreasing).
Business Trust Law & Legal Definition. Business trust is a form of business organization which is similar to a corporation, in which investors receive transferable certificates of beneficial interest.n some states, a business trust is subject to the laws of trusts whereas in other states the laws of corporations or partnerships govern its existence.
Standard Oil Trust. The company continued to prosper and expand its empire, and, in 1882, all of its properties and those of its affiliates were merged into the Standard Oil Trust, which was, in effect, one huge organization with tremendous power but a murky legal existence. It was the first of the great corporate trusts.