Signal Gain, Feedback & Control Dynamics

Primes about how systems amplify, filter, or regulate a signal through gain and feedback loops: distortion and nonlinear amplification (harmonic distortion, convolution, eigenvectors), homeostatic overshoot and rebound (withdrawal rebound, eutrophication, overshoot and collapse), and control-loop limits on bandwidth and range (feedforward, gain control, selectivity window, supernormal stimulus).

24 primes in this family — primes that sit near one another in abstraction space (k-means over structural-signature embeddings). Each is shown with its short description.

• Amplification — Increase signal or disturbance.
• Convolution — Each output is a sliding, weighted local mixture of an input produced by one fixed kernel.
• Crossover Interaction — The same input moves an outcome in opposite directions across levels of a second condition, so neither factor has a context-free sign and a main-effect average can cancel the mechanism to zero.
• Diminishing Incremental Gains — Reduced benefit per unit.
• Distortion — Systematic, mapping-induced deviation of an output from a faithful rendering of its input.
• Efficiency Rebound — An efficiency gain lowers the effective cost per unit of an activity, inducing enough additional demand to offset part or all of the resource saving expected at fixed activity volume.
• Eigenvalue And Eigenvector — A transformation's invariant directions and the scalars by which it stretches them.
• Eutrophication — An enabling input crosses an assimilation ceiling and inverts into a degrading load, driving a self-amplifying bloom that depletes a secondary resource and locks in a worse regime.
• Feedback — Outputs influence inputs.
• Feedforward — A predictive model of an action's consequences is interposed upstream of commitment, so the actor pre-corrects rather than waits for a deviation to feed back.
• Feedforward Inhibition — The same input that activates a downstream element simultaneously recruits a brake on it along a parallel path, so the response is shaped by their difference.
• Gain Control — A slow secondary loop continuously retunes the gain of a fast forward signalling pathway so it stays in its useful range across changing input statistics.
• Garbage In, Garbage Out — The quality of a transformation's output is bounded above by the quality of its inputs; no downstream sophistication can repair defects already present in the input.
• Harmonic Distortion — Passing a signal through a nonlinear transfer function generates new frequency components — harmonics and intermodulation products — absent from the input, an artifact of the nonlinearity itself rather than of any sampling or discretization.
• Intrinsic Ceiling vs Input — An intervention is characterised by two independent and routinely conflated parameters — the intrinsic ceiling of effect it can produce, and the input required to push the response close to that ceiling — which can vary separately and which determine the right choice depending on which binds.
• Neuromodulation — A separate, diffuse control channel sets the gain or operating mode by which a system processes content, without itself carrying content.
• Overshoot and Collapse — An enabling input that is beneficial at low levels crosses an assimilation ceiling and inverts into a self-amplifying degrading load, depleting a secondary resource and locking in a hysteretic worse regime that does not reverse when the input is removed.
• Pull Flow — An activity is triggered by a downstream demand signal rather than scheduled by an upstream producer, shifting uncertainty absorption from inventory to latency.
• Reciprocal Additivity (Optic Equation) — Relate nonzero inputs to one effective result by requiring the reciprocal of the result to equal the sum of the input reciprocals, so parallel contribution becomes ordinary addition after reciprocal transformation.
• Recursive Attenuating Amplification — A one-shot input recirculating through a leaky operator with sub-unit retention produces a bounded total response of input/(1−k).
• Reference Cadence Exceeds Tracking Bandwidth — When the signal a closed loop must track changes faster than the loop's bandwidth, persistent error follows that no amount of executor effort can close.
• Selectivity Window — A process discriminates among targets only inside a bounded operating range of a control parameter, and loses or reverses that discrimination outside it.
• Supernormal Stimulus — A response circuit calibrated only over a natural cue range, with no built-in ceiling, is hijacked by an engineered referent that exceeds that range and triggers disproportionate response.
• Withdrawal Rebound — A system that adapted to a sustained input by mounting an opposing internal compensation overshoots in the opposite direction when the input is abruptly removed, because the now-unopposed compensation is still pushing against an input that is no longer there.