S and L spaces

In the context of functional spaces in mathematics, "S" and "L" typically refer to certain types of spaces of functions with particular properties. Here are the common definitions: 1. **S Spaces**: Often, "S spaces" refer to the **Schwartz Space** (denoted as \( \mathcal{S} \)). This space consists of rapidly decreasing smooth functions that, along with all their derivatives, vanish faster than any polynomial as their argument goes to infinity.