# Definition DIFO-1

This [test](.) is exercising the case [1](../Readme.md) of the definition [DIFO](../../difo/Readme.md).

### Description

In this test, the symbol `⟲` is used as *free operator*. But `⟲` is a *special symbol* (used in symbolic forms of *across loops*). This violates `DIFO-1`.
