A set of common restrictions between different parties separated by membranes

Consider the situation in the image below. One could say that Alice’s distortion of the DOM object has a set of restrictions (or constraints) that limit Alice’s knowledge of the DOM’s attributes and possible operations and her ability to perform operations on it, and Bob’s distortion also has a set of restrictions that is potentially different from Alice’s. If Alice sends Bob a request to perform an operation on the DOM through his distortion, he may not be able to complete the request unless he knows about the necessary attributes and operations and can perform the necessary operation. This prompts the notion of a set of restrictions that is common between Alice’s and Bob’s distortions. Having such a notion may be useful in determining which of Alice’s requests to Bob may or should fail. A request may fail in a scenario like the one described above, and a request should fail if Alice is malicious and tries to mount a confused deputy attack (i.e., Alice asks Bob to perform an operation she herself is restricted from performing on the DOM).