(=> or a thin right arrow) A binary
Boolean function
and logical connective. A => B is true unless A is true and
B is false. The
truth table is
A B | A => B
----+-------
F F | T
F T | T
T F | F
T T | T
It is surprising at first that A => B is always true if A is
false, but if X => Y then we would expect that (X & Z) => Y
for any Z.