Formalism

Heisenberg seems to have been motivated by his intense annoyance that Schrödinger's more intuitive version of quantum theory was more widely accepted than his own, even though both formalisms led to the same results.

Dirac approaches quantum mechanics by means of a so-called symbolic method, the bracket formalism. Although this formalism has a mathematical flavour, in fact, it is based upon bold claims which lack mathematical foundation.

1992, tuart M. Shieber, Constraint-based Grammar Formalisms, The MIT Press, page 51, It is this abstraction that justifies considering these methods as characterizing constraint-based formalisms in general, rather than an individual formalism.