Symmetric tangent conductance of transistor edges

Determine whether a transistor edge has a symmetric tangent conductance so that the reciprocity capacity bound applies to its small-signal response.

Background

The universal theorem applies to systems whose linearized operator is symmetric. The paper notes that nonlinear transistor-based analogue networks require examining the tangent operator at the trained operating point rather than the global input–output map.

For transistor elements, it is unresolved in the paper whether the tangent conductance is symmetric. Moreover, the cited hardware uses imposed inputs, so even a symmetric tangent operator would need to be combined with the appropriate imposed-displacement response law.

References

Whether a transistor edge has a symmetric tangent conductance is a question about its element law that we do not settle, and their drive is in any case the imposed one of Sec.~\ref{sec:dirichlet}; the two layouts of theirs in Table~\ref{tab:layouts} are counted for their driven and read-out sets alone, which is all the fraction eq:fracgen needs.

— Reciprocity can halve what a mechanical network can learn  (2609.04169 - Vu et al., 3 Sep 2026) in Section 2, subsection “The bound is a statement about symmetric operators”