Reactive integrated development environments for software engineering have lead to an increase in productivity and quality of programs produced. They have done so by replacing the traditional sequential compile, test, debug development cycle with a more integrated and reactive development environment where these tools are run automatically in the background, giving the engineer instant feedback on his most recent change.

The RODIN platform provides a similar reactive development environment for formal modeling and proof. Using this reactive approach places new challenges on the proof tool used. Since proof obligations are in a constant state of change, proofs in the system must be represented and managed to be resilient to these changes. This paper presents a solution to this problem that represents proof attempts in a way that makes them resilient to change and amenable to reuse.