topological defect

CSGnet Archive CSG2014
1

[Martin Taylor 2014.08.27.23.19]

Yes. I thought I pointed that out in both words and equations, but

on re-reading my message I guess I wasn’t as clear about it as I had
thought.
Martin

···

[From Rick Marken (2014.08.27.1525)]

            Martin Taylor

(2014.08.27.16.06)_-

            MT: The essential point of a control system is not the

negative feedback as such, but the delivery of energy
from a separate source to counter the effects of
external disturbances.

      RM: How about they are _both_ essential, since the delivery of

energy from a separate source will reinforce rather
than counter the effects of external disturbances if
the energy is delivered in a positive feedback loop (in which
case you get the loop input variable “running away”, as in
microphone feedback, rather than being controlled).