A perturbation function is used in mathematics and physics to represent small changes or disturbances to a system's parameters or variables. It helps in analyzing the effects of these perturbations on the overall behavior of the system.

We discovered that the perturbation was coming from a fight in the neighbor's yard.

Frank Herbert Brownell has written:

'Explicit perturbation formulae and convergence theorems' -- subject(s): Convergence, Perturbation theory (Mathematics), Perturbation (Mathematics)

Ji-Huan He has written:

'Perturbation methods' -- subject(s): Perturbation (Mathematics)

Perturbation