The document discusses Variable Entered Maps (VEM), which is a technique used to simplify Boolean equations when the number of variables exceeds what can easily be managed with a K-map. VEM allows a smaller K-map to handle more variables by allowing a single variable or expression to be entered into each cell. An example is given where D is used as the Variable Entered Map to simplify the Boolean expression y=f(A,B,C,D) using a smaller K-map than would otherwise be needed. VEM can help solve problems involving multiplexers by allowing an n-variable problem to be plotted on an n-1 variable map.