Define inc$/2$ that holds only when its second argument is an integer one larger than its

first argument. For example, inc$(4,5).$ should return true, but inc$(4,6).$ should

not, or inc$(4,$X$).$ would result in X $=5.$ Unfortunately, because of the use of is$,$ we

would not be able to ask inc$($X$,5).$ Why? $($Type your answer in the header comments

of the program$).$