The BETWEENLEFTEXCLUSIVE built-in function returns a bit(1) value that indicates whether the first argument x is in the left-open interval as defined by the second argument a and the third argument b.
>>-BETWEENLEFTEXCLUSIVE(x,a,b)---------------------------------><
BETWEENLEFTEXCLUSIVE(x,a,b) is equivalent to the test (a < x ) & (x <= b). Therefore, if any of the arguments are numeric, they must be REAL.