Rate-optimal estimation of mixed semimartingales.
Ann. Stat. 53, 219-244 (2025)
Consider the sum Y = B + B(H) of a Brownian motion B and an independent fractional Brownian motion B(H) with Hurst parameter H ∈ (0, 1). Even though B(H) is not a semimartingale, it was shown by Cheridito (Bernoulli 7 (2001) 913–934) that Y is a semimartingale if H > 3/4. Moreover, Y is locally equivalent to B in this case, so H cannot be consistently estimated from local observations of Y. This paper pivots on another unexpected feature in this model: if B and B(H) become correlated, then Y will never be a semimartingale, and H can be identified, regardless of its value. This and other results will follow from a detailed statistical analysis of a more general class of processes called mixed semimartingales, which are semiparametric extensions of Y with stochastic volatility in both the martingale and the fractional component. In particular, we derive consistent estimators and feasible central limit theorems for all parameters and processes that can be identified from high-frequency observations. We further show that our estimators achieve optimal rates in a minimax sense.
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Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Typ der Hochschulschrift
Herausgeber
Schlagwörter
Central Limit Theorem ; High-frequency Observations ; Hurst Parameter ; Kl Divergence ; Minimax Rate ; Mixed Fractional Brownian Motion ; Rough Noise
Keywords plus
Sprache
englisch
Veröffentlichungsjahr
2025
Prepublished im Jahr
0
HGF-Berichtsjahr
2025
ISSN (print) / ISBN
0090-5364
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ISBN
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Band: 53,
Heft: 1,
Seiten: 219-244
Artikelnummer: ,
Supplement: ,
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Verlag
Institute of Mathematical Statistics (IMS)
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0000-00-00
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Prüfer
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0000-00-00
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0000-00-00
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weitere Inhaber
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Begutachtungsstatus
Peer reviewed
Institut(e)
Institute of Epidemiology (EPI)
POF Topic(s)
30202 - Environmental Health
Forschungsfeld(er)
Genetics and Epidemiology
PSP-Element(e)
G-504091-001
Förderungen
Copyright
Erfassungsdatum
2025-05-06