Paul strich did business as an optician in duluth, minnesota. paul used only the products of the plymouth optical co., a national manufacturer of optical products and supplies with numerous retail outlets and some franchise arrangements in areas other than duluth. to increase business, paul renovated his office and changed the sign on it to read "plymouth optical co." paul did business this way for more than three years"advertised under that name, paid bills with checks bearing the name of plymouth optical co., and listed himself in the telephone and city directories by that name. plymouth immediately became aware of what paul was doing. however, because paul used only plymouth products and plymouth did not have a franchise in duluth, it saw no advantage at that time in prohibiting paul from using the name and losing him as a customer. paul contracted with the duluth tribune for advertising, making the contract in the name of plymouth optical co. when the advertising bill was not paid, the duluth tribune sued plymouth optical co. for payment. plymouth's defense was that it never authorized paul to do business under the name, nor authorized him to make a contract with the newspaper. decide.