Boolean expression question
A dot is one traditional symbol for AND in Boolean notation. If it were NAND, it would have an over-bar over the dotted terms. Similarly, plus is one traditional symbol for OR, and the usual companion to dot for AND, and NOR would typically be expressed as an over-bar over the plussed terms. So, I think your answer looks like a faithful implementation of the expression. 

The other common symbols that are used are ^ for AND and v for OR.