You may have noticed that in practice problems related to order, logarithms are usually just "log". As you know from algebra, there is more than one logarithm. For each positive number b, there is a base-b logarithm. They are all different- the base-2 logarithm of 8 is 3, while the base 10 logarithm of 8 is 0.90308998699... . There is also a base-e logarithm, called the natural logarithm and usually written as "ln". This begs the question of how it could be justified to just say that a function f(n) is order of "log(n)". Isn't this meaningless if the base of the log is not specified?