May carry on a business competing with that of the firm, but, subject to contract to the contrary, he may not use the firm name.

May carry on a business competing with that of the firm, but, subject to contract to the contrary, he may not represent himself as carrying on the business of firm. 

May carry on a business competing with that of the firm, but, subject to contract to the contrary, he may not solicit the old customers who were dealing with the firm.