theorem Lm20B: :: FUZZY_7:33

for a, b, c being Real
for f being Function of REAL,REAL st b > 0 & c > 0 & ( for x being Real holds f . x = max (0,(b - |.((b * (x - a)) / c).|)) ) holds
( f . (lower_bound ['(a - c),(a + c)']) = 0 & f . (a - c) = 0 & f . (upper_bound ['(a - c),(a + c)']) = 0 & f . (a + c) = 0 )