(calculus) A differential operator that preserves mathematical smoothness.

plural of operating theatre

plural of operating room

In the work (already) cited or quoted. Used, typically in footnotes and endnotes, to cite in an abbreviated form a source that has been cited previously; frequently abbreviated as op. cit.

plural of smooth operator

A covert operation typically involving activities that are highly clandestine and outside of standard military protocol.

plural of black operation

Alternative spelling of uncooperative

plural of tour operator

(mathematics, functional analysis) An operator L such that for functions f and g and scalar λ, L (f + g) = L f + L g and L λf = λ L f.