Co-existence asks whether the product can share an environment with other products without harming them or being harmed. A measure relates conflicts observed to the environments tested. The population is a set of environments, each with named products and versions. A co-existence result without that list is not reproducible. Conflicts are often resource conflicts: a port, a file lock, a shared library, a device, a scheduled job. The measure should separate a conflict that stops operation from one that degrades it, because the two need different responses. The family is small but it is where a product fails in a customer environment after passing every test in isolation.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.