My own experience is that I dont see lg so I must assume that its use is unusual. One also frequently uses the notation log k for the k -th iterate of this function. Logarithm is a very useful mathematical concept that helps in solving complex math problems.
Learn logarithm and natural logarithm differences with example at BYJUS.
Natural logarithm can be calculated using the python module called math. Like p e is a mathematical constant and has a set value. So log3 and log103 are one and the same thing the same way x and 1x are the same thing. Thats ell-enn not one-enn or eye-enn Just as the number e arises naturally in math and the sciences so also does the natural log which is why you need to be familiar with it.