There are many ways to divide mathematics into two-culture dichotomies. An important one is the
Discrete vs. the Continuous. Until almost the end of the 20th century, the continuous culture was
dominant, as can be witnessed by notation. An important family of Banach spaces of continuous
functions is denoted by L^p , with a Capital L, while their discrete analogs are denoted by the lowercase
counterpart l^p. A function of a continuous variable is denoted by f(x), where the continuous
output, f, is written at the same level as the continuous input x, but if the input is discrete, then
the function is given the derogatory name sequence, and written a_n, where the continuous output,
a, looks down on the discrete input, n.