The notation $\{ f(x), g(x) \}$ typically refers to a set containing two functions: $f(x)$ and $g(x)$. A set is simply a collection of elements, in this case the two functions.

So, $\{ f(x), g(x) \}$ would represent a set where $f(x)$ and $g(x)$ are the elements. If there's more context, such as a specific operation being applied between $f(x)$ and $g(x)$, that could change the interpretation.

For example:

• If you're asking about the set of the two functions, it would just be $\{ f(x), g(x) \}$.
• If you're asking about a bracket used in the context of an inner product or another operation, I would need more specifics on the problem.

Do you have more context for the expression $\{ f(x), g(x) \}$? Would you like more details on sets, operations, or specific use cases?