Functional integration: Difference between revisions

Revision as of 06:45, 3 December 2019

Revision as of 06:45, 3 December 2019

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{{Confusing|section|date=January 2014}}

{{unreferenced section|date=March 2017}}

Whereas standard ][[Riemann integral|Riemann integration]] sums a function ''f''(''x'') over a continuous range of values of ''x'', functional integration sums a [[functional (mathematics)|functional]] ''G''[''f''], which can be thought of as a "function of a function" over a continuous range (or space) of functions ''f''. Most functional integrals cannot be evaluated exactly but must be evaluated using [[perturbation methods]]. The formal definition of a functional integral is

:<math>