What is the meaning of "when [tex] x_{1}, ..., x_{n}[/tex] are permuted in all possible ways, the number of different values of [tex]f (x_{1}, ..., x_{n})[/tex] is a divisor of n!"?

What is the meaning of when tex x1 xntex are permuted in all possible ways the number of different values of texf x1 xntex is a divisor of n class=