Girsanov theorem
E9114
Girsanov theorem is a fundamental result in stochastic calculus that describes how the dynamics of stochastic processes, particularly Brownian motion, change under an equivalent change of probability measure.
Observed surface forms (1)
| Surface form | Occurrences |
|---|---|
| Girsanov’s theorem | 1 |
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
result in stochastic calculus
ⓘ
theorem ⓘ |
| appliesTo |
Brownian motion
ⓘ
Itô processes ⓘ continuous-time stochastic processes ⓘ semimartingales ⓘ |
| category |
theorems in probability theory
ⓘ
theorems in stochastic processes ⓘ |
| concerns |
adapted processes
ⓘ
semimartingale characteristics ⓘ |
| coreConcept |
Radon–Nikodym derivative
ⓘ
drift transformation ⓘ equivalent change of probability measure ⓘ exponential martingale ⓘ martingale measure ⓘ |
| describes |
change of dynamics of stochastic processes under change of measure
ⓘ
how Brownian motion changes under an equivalent change of probability measure ⓘ |
| enables |
construction of equivalent martingale measures
ⓘ
removal of drift from stochastic differential equations by measure change ⓘ |
| field |
probability theory
ⓘ
stochastic analysis ⓘ stochastic calculus ⓘ |
| formalizedIn | measure-theoretic probability ⓘ |
| generalizes | change-of-measure techniques in classical probability ⓘ |
| holdsOn | filtered probability spaces ⓘ |
| implies |
drift terms can be removed or introduced by changing measure
ⓘ
local martingales under one measure may become martingales under another ⓘ |
| namedAfter | Igor Vladimirovich Girsanov ⓘ |
| relatedTo |
Cameron–Martin theorem
ⓘ
Doob–Meyer decomposition ⓘ Feynman–Kac formula ⓘ martingale representation theorem ⓘ |
| requires |
Novikov condition or similar integrability condition
ⓘ
absolute continuity of measures on the underlying filtration ⓘ existence of an equivalent probability measure ⓘ |
| statesThat |
a process that is Brownian motion under one measure becomes a Brownian motion with drift under another equivalent measure
ⓘ
under an equivalent change of measure the Brownian motion acquires a drift term ⓘ |
| typicalAssumption |
Brownian motion with respect to a given filtration
ⓘ
integrability of the drift process ⓘ |
| usedIn |
change from physical measure to risk-neutral measure
ⓘ
derivative pricing ⓘ filtering theory ⓘ large deviations theory ⓘ mathematical finance ⓘ risk-neutral valuation ⓘ stochastic control ⓘ |
| uses |
Itô calculus
ⓘ
Radon–Nikodym derivative to define new measure ⓘ stochastic exponentials ⓘ |
Referenced by (5)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Girsanov’s theorem