The beauty of bitwise AND
Can someone explain this sentence to me?(In the quote below, he names the AND function "f", which in itself is a bit strange. What's wrong with "and" or ∧?)  f(a, b) produces at most a or b, whichever is greater:
    f(a, b) ≤ max(a, b)

As far as I can tell, the result can never be greater than the smaller of a and b. I can't come up with a counterexample. Is there one?