It is ultimately from Latin infīnītus, the opposite of fīnītus, meaning "finite." The notion of smallness in infinitesimal derives from the mathematical concept that a quantity can be divided endlessly; no matter how small, it can be subdivided into yet smaller fractions, or infinitesimals. ...
Hence, the infinitesimally deformed field theories and string theories are constructed. The physical meaning of these theories is discussed.AhmedE.HegaziA.S.EBSCO_AspJournal of Mathematical PhysicsE.Ahmed, A.S.Hegazi A.S.: Infinitesimally deformed field and string theories. J.Math.Phys.33(1):...