This functionality distinguishes between user-defined symbolic constants and variable parameters.

In the following case,  is a variable parameter:

Whereas, in the following situation, alpha is a user-defined symbolic constant, and it must be matched exactly by "alpha" for the pattern to be successfully returned. The first call to fouriercos will not return an answer for this reason--because 4 is not the same as alpha--while the second will.

The rest of these examples use variable parameters as opposed to symbolic constants:

You can specify conditions on the parameters to be matched:

With invmellin and hankel, arguments are added to the addtable function, as arguments are added to the transforms themselves. These arguments can be varied, introducing greater flexibility in the information that can be added to user-defined tables.