DT FAQ: What is Digital Twin ModSim equivalency?

What is Digital Twin Modeling & Simulation (ModSim) equivalency?

FAQ Variant(s): How are Digital Twins related to other Digital Twins?

Consider that Digital Twins can be Verified & Validated (V&V-ed) using the pragmatic test described in DE FAQ: How can one Verify & Validate (V&V) a Digital Twin? and reproduced below:

A reasonable litmus test for a "Digital Twin" is analogous to the Turing Test for AI. Suppose you have a System Tester (ST), a Physical System Twin (PT), and a Digital Twin (DT) for PT. If the ST can run a robust system Verification & Validation (V&V) Test Suite on both PT and DT, but cannot reliably distinguish between them with a probability > 80%, ∴ DT is a bona fide Digital Twin of PT. — Digital Engineering Group

It consequently follows that, from a Systems Integration & Testing perspective:

IF DT1 = digitalTwin(PT) AND DT2 = digitalTwin(PT)
THEN DT1 ≈ PT ≈ DT2

Compare and contrast Turing Machine equivalency.