Mathematical motivation [connes-000Q]

This draft expands the mathematical motivation summarized in § [connes-000Z].

The counterexample is not merely a negative answer to Connes' conjecture. Its richer content is a controlled experiment in nonfaithfulness. The three proof families vary different algebraic inputs while preserving the analytic output.

The group distinction survives algebraically but disappears after measurable crossed-product transport.

Three kinds of information loss stand out:

  • Cocycle: algebraically nontrivial, measurably removable;
  • Action: Fourier–Pontryagin transport conjugates distinct module actions; and
  • Extension data: characteristic-two data distinguish groups while their factors remain isomorphic.

Property (T) acts as a control condition: these are rigid groups, not examples explained by group-theoretic flexibility. The comparison asks which algebraic distinctions survive representation, twisting, duality, and analytic completion, and at which step the others disappear.