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corresponding proof, ๐‘„๐œƒ โŠ—2=0if๐‘‹is obtained by discrete sampling from an affine process. For the following statement we introduce some more notation. Set ฬ‚๐‘‹๐œƒ(๐‘ก)โˆถ=ฬ‚๐‘‹๐œƒ(๐‘ก,๐‘กโˆ’1), ๐‘‰๐œƒ(๐‘ก)โˆถ=๐‘‰๐œƒ(๐‘ก,๐‘กโˆ’1),๐‘Š๐œƒ(๐‘ก)โˆถ=๐‘Š๐œƒ(๐‘ก,๐‘กโˆ’1),๐‘‹๐œƒ(๐‘ก)โˆถ=(๐‘‹(๐‘ก),ฬ‚๐‘‹๐œƒ(๐‘ก),๐‘‰๐œƒ(๐‘ก))as well as ๐พ๐œƒโˆถ=๐ด๐œƒฬ‚ฮฃ๐œƒ โˆถ,o(ฬ‚ฮฃ๐œƒ o)โˆ’1, ๐น๐œƒโˆถ=๐ด๐œƒโˆ’...
https://arxiv.org/abs/2503.05590v1
๐‘ก๐‘ก โˆ‘ ๐‘ =1๐‘ก โˆ‘ ๐‘ข=1Cov๐œ—[๐‘๐œ—(๐‘ ,๐‘ โˆ’1),๐‘๐œ—(๐‘ข,๐‘ขโˆ’1)] using a non-parametric kernel estimator, also called heteroskedastic autocorrelation consis- tent (HAC) estimator or Neweyโ€“West estimator, see Andrews [8] or Newey and West [87]. Alternatively, extending a result of Francq et al. [58], Boubacar Ma ยจฤฑnassara and Fra...
https://arxiv.org/abs/2503.05590v1
of the form ๐‘ˆ๐œ—=โˆซ(๐‘”๐œ—(๐‘ฅ)๐‘”๐œ—(๐‘ฅ)โŠคโˆ’โ„Ž๐œ—(๐‘ฅ)โ„Ž๐œ—(๐‘ฅ)โŠค)๐œ‡๐œ—(๐‘‘๐‘ฅ), ๐‘Š(๐œ—)=โˆซฬƒ๐‘“๐œ—(๐‘ฅ)๐‘‘๐œ‡๐œ—(๐‘‘๐‘ฅ). As a consequence, these matrices can be computed as follows if Assumption Aโ€™ holds: Algorithm 3.12. Step 1: Since๐‘‹is a polynomial state space model of order 4, we have that ๐”ผ๐œƒ(๐‘‹(๐‘ก)๐œ†||F๐‘กโˆ’1)=โˆ‘ ๐œ‡โˆˆโ„•๐‘‘ 4๐‘๐œ†,๐œ‡๐‘‹(๐‘กโˆ’1)๐œ‡,...
https://arxiv.org/abs/2503.05590v1
sequence (ฬ‚๐œƒ๐‘(๐‘ก))๐‘กโˆˆโ„•is weakly๐œ—-consistent and more- over that (โˆš๐‘ก(ฬ‚๐œƒ(๐‘ก)โˆ’๐œ—),โˆš๐‘ก(ฬ‚๐œƒ๐‘(๐‘ก)โˆ’๐œ—))๐‘กโˆˆโ„•is jointly asymptotically normal. In this case, since ๐œ—โˆˆ int(ฮ˜) , the Lagrange multiplier theorem (see e.g. Fitzpatrick [57, Theorem 17.17]) and consistency imply that, with probability converging to 1, ฬ‚๐œƒ๐‘(๐‘ก)s...
https://arxiv.org/abs/2503.05590v1
of a general multivariate L ยดevy-driven Ornstein-Uhlenbeck process. 4.1 The Heston stochastic volatility model In the stochastic volatility model of Heston [63], the asset ๐‘†=(๐‘†(๐‘ก))๐‘กโˆˆโ„+incorporates a stochas- tic variance component ๐‘ฃ=(๐‘ฃ(๐‘ก))๐‘กโˆˆโ„+which is driven by a square-root diffusion. More specif- ically, it i...
https://arxiv.org/abs/2503.05590v1
polynomial state space model in the sense of Definition 2.1. For computational simplicity, we consider fixed drift parameter ๐œ‡= 0and volatility response parameter ๐›ฟ=1 2so that the log-spot process ๐‘Œfrom (4.3) has the form d๐‘Œ(๐‘ก)=โˆš ๐‘ฃ(๐‘ก)d๐‘Š(1)(๐‘ก), (4.4) 22 which is a martingale. Then ฮ”๐‘Œ=(๐‘Œ(๐‘ก)โˆ’๐‘Œ(๐‘กโˆ’1))๐‘กโˆˆโ„•is th...
https://arxiv.org/abs/2503.05590v1
[88] together with the expressions from Section 3.3 in Al `os and Lorite [6]. 23 estimation framework. We did not test the effect of these model modifications concerning the efficiency of the resulting quasi-maximum likelihood estimator, say by examining the result- ing differences in size of the asymptotic variances o...
https://arxiv.org/abs/2503.05590v1
ฬ‚ ๐œŽ(๐‘ก)is larger by approximately a factor of 1.5 compared to the isolated estimation. Interestingly however, 05106 10106 15106 20106 161718192021Standard deviation for (t) Isolated estimation of the parameters 05106 10106 15106 20106 16182022Joint estimation of the parameters 05106 10106 15106 20106 0.420.440.46Stand...
https://arxiv.org/abs/2503.05590v1
15106 20106 Number of observations t0.2 0.1 0.00.10.20.30.40.50.6 Corr*[,m] Corr*[,] Corr*[m,] Figure 4: For each pair of estimator components, the figure displays five independent se- quences of estimator correlations, respectively obtained from the covariance estimates ฬ‚๐‘‰๐‘ก[ฬ‚๐œƒ(๐‘ก)] for๐‘กvarying between 1 and 20โ‹…106...
https://arxiv.org/abs/2503.05590v1
of rejection under the null ๐ป0โˆถ๐œŽโˆ—= 0.3for the Wald, the LM and the LR test. Asymptotically, these sizes of the tests fall theoretically within the given confidence intervals in the fifth column with a probability of 95%. ๐‘-values of the sizes are given below. scale. To this end, one may define the polynomial state s...
https://arxiv.org/abs/2503.05590v1
Proposition 4.4. Let๐‘‹be an Ornsteinโ€“Uhlenbeck process with background driving L ยดevy process ๐ฟ. Let๐‘โˆˆ[1,โˆž)and suppose that ๐”ผ(โ€–๐ฟ(1)โ€–๐‘)<โˆž(or equivalently โˆซโ€–๐‘ฅโ€–โ‰ฅ1โ€–๐‘ฅโ€–๐‘๐œˆ๐ฟ(d๐‘ฅ)<โˆž, where ๐œˆ๐ฟis the L ยดevy measure of ๐ฟ). Then ๐”ผ(โ€–๐‘‹(๐‘ก)โ€–๐‘)<โˆžfor any๐‘กโˆˆโ„+. If moreover ๐›ผ(๐‘„)>0, i.e.๐‘„ has only eigenvalues with positi...
https://arxiv.org/abs/2503.05590v1
on strong mixing properties and all in all less elementary than those introduced in Section 2.1. We will now briefly treat the fulfilment of the Assumptions Aโ€™, B, Cโ€™ from Section 2.1 for a parametric Ornsteinโ€“Uhlenbeck polynomial state space model ๐‘‹parameterised by some ๐œƒโˆˆ ฮ˜, whereฮ˜is a convex and compact subset of ...
https://arxiv.org/abs/2503.05590v1
the short rate, where the short rate can be thought of as some sort of instantaneous forward interest rate with infinitesimal horizon. For details about interest rate models in general and the example considered here see Chapter 14 and Example 14.10 in Eberlein and Kallsen [44], respectively. In our case we assume that...
https://arxiv.org/abs/2503.05590v1
components assumed to be known. Figure 6 shows ten independent sequences (ฬ‚๐›ฟ(๐‘ก))๐‘กโˆˆ{1,โ€ฆ,๐‘‡}of the quasi-maximum likelihood estimator, first if the latent mean ๐‘šis assumed to be unobservable and secondly if ๐‘šis assumed to be observable. Again as in the case of the Heston model, introducing additional observable comp...
https://arxiv.org/abs/2503.05590v1
ten se- quences of asymptotic estimator correlations obtained from ฬ‚๐‘‰๐‘ก[ฬ‚๐œƒ(๐‘ก)]. Black lines show values obtained from the explicit calculations detailed in Section 3.3. of๐›ฟwith the latent mean ๐‘štreated as unobservable. Next to a kernel density estimate, we again show the Gaussian density corresponding to a mean of...
https://arxiv.org/abs/2503.05590v1
the state transition matrix ๐ด๐œƒof๐‘‹is given by ๐ด๐œƒ ๐‘–๐‘—=โˆ’i๐œ•๐‘ข๐‘–ฮจ๐œƒ ๐‘—(0)for๐‘–,๐‘—โˆˆ{1,โ€ฆ,๐‘‘}, which follows by differentiation in (5.1) and ๐œ‘๐œƒ ๐‘ก(0)=1 . Moreover, ๐”ผ๐œƒ[๐‘‹๐‘–(๐‘ก+1)๐‘‹๐‘—(๐‘ก+1)|F๐‘ก]=โˆ’๐œ•๐‘ข๐‘–๐œ•๐‘ข๐‘—๐œ‘๐œƒ ๐‘ก(0)=โˆ’๐œ•๐‘ข๐‘–[(๐œ•๐‘ข๐‘—๐œ“๐œƒ(๐‘ข,๐‘ก))๐œ‘๐œƒ ๐‘ก(๐‘ข)]|||๐‘ข=0 =โˆ’๐œ•๐‘ข๐‘–๐œ•๐‘ข๐‘—๐œ“๐œƒ(0,๐‘ก)โˆ’(๐œ•๐‘ข๐‘–๐œ“๐œƒ(0,๐‘ก))(๐œ•๐‘ข๐‘—๐œ“๏ฟฝ...
https://arxiv.org/abs/2503.05590v1
definite. 5.2 Proofs for Section 3.1 Proof of Proposition 3.5. For๐‘กโˆˆโ„•โˆ—the matrices ฬ‚ฮฃ๐œƒ(๐‘ก+1,๐‘ก)andฬ‚ฮฃ๐œƒ(๐‘ก,๐‘ก)are positive definite because the matrices ๐ถ๐œƒ(๐‘ก)are positive definite (see Proposition 2.13) and hence all pseudoin- verses occurring in Proposition 2.8 are proper inverses. The result now follows by differ...
https://arxiv.org/abs/2503.05590v1
= โˆ’๐‘กฬƒ๐‘๐œ—(๐‘ก)โˆ’11โˆš๐‘ก๐‘๐œ—(๐‘ก)and the right-hand side converges in โ„™๐œ—-law toโˆ’๐‘Š(๐œ—)โˆ’1๐‘ by Slutskyโ€™s theorem. Since โ„™๐œ—(๐ถ๐‘ก)โ†’1as๐‘กโ†’โˆž, this concludes. The main goal of Sections 5.2.1โ€“5.2.3 is to establish the various conditions from Proposi- tions 5.2 and 5.3 in order to prove Theorems 3.3 and 3.4. The following Section...
https://arxiv.org/abs/2503.05590v1
or Schlemm and Stelzer [100], our approach of using Markovianity of an augmented version of the original process seems to be novel in the context of quasi-maximum likelihood estimation. The usual path to proving asymptotic normality of the quasi-score process consists in using certain strong mixing prop- erties for the...
https://arxiv.org/abs/2503.05590v1
and ๐ท๐œƒ(๐‘ก)โˆถ=๐ถ๐œƒ(๐‘ก)โˆ’๐ถ๐œƒ, see Anderson and Moore [7, Problem 4.5]. By iterating this equation one obtains ฬ‚ฮฃ๐œƒ(๐‘ก)โˆ’ฬ‚ฮฃ๐œƒ=(๐ด๐œƒโˆ’๐พ๐œƒ๐ป)๐‘กโˆ’1(ฬ‚ฮฃ๐œƒ(1)โˆ’ฬ‚ฮฃ๐œƒ)ฮจ๐œƒโŠค ๐‘ก,1+๐‘กโˆ’2 โˆ‘ ๐‘ =0(๐ด๐œƒโˆ’๐พ๐œƒ๐ป)๐‘ ๐ท๐œƒ(๐‘กโˆ’๐‘ )ฮจ๐œƒโŠค ๐‘ก,๐‘กโˆ’๐‘ . (5.10) Let๐น๐œƒโˆถ=๐ด๐œƒโˆ’๐พ๐œƒ๐ป. We now argue that ๐œŒ(๐น๐œƒ)โ‰ค๐›ผfor any๐œƒโˆˆ ฮ˜ and some๐›ผโˆˆ [0,1). Analogously to...
https://arxiv.org/abs/2503.05590v1
tingale difference sequence for ๐‘‹๐œƒfrom (5.5). Then there exists a matrix ๐ด๐œƒโˆˆโ„๐‘‘(๐‘˜+2)ร—๐‘‘(๐‘˜+2)with ๐œŒ(๐ด๐œƒ)<1such that๐ด๐œƒ(๐‘ก)โ†’๐ด๐œƒuniformly in ๐œƒat a geometric rate. Moreover, the homogeneous Markov chain ๐‘‹๐œƒ,homwith๐‘‹๐œƒ,hom(0)โˆถ=๐‘‹๐œƒ(0)and๐‘‹๐œƒ,hom(๐‘ก)โˆถ=ฬ‚ ๐‘Ž๐œƒ 1+๐ด๐œƒ๐‘‹๐œƒ,hom(๐‘กโˆ’1)+๐‘๐œ—(๐‘ก)is a polynomial state spa...
https://arxiv.org/abs/2503.05590v1
letโŠ•denote the usual Minkowski sum of subsets of โ„๐‘‘. Define the set R๐œƒโˆถ=โˆž โจ ๐‘ =0(๐น๐œƒ)๐‘ ๐บ๐œƒ(๐ธ)โˆˆB(โ„๐‘‘) (5.15) and letR๐œƒ ๐‘Žโˆถ=R๐œƒ+๐‘Ž๐œƒ. Since๐ธis a connected smooth manifold containing 0, R๐œƒโˆ‹ 0is a connected smooth manifold too, and the partial sums in (5.15) form an increasing sequence of sets. Suppose that the sta...
https://arxiv.org/abs/2503.05590v1
any๐‘โˆˆ[1,โˆž). Since๐‘‹has uniformly bounded moments of order 4+๐›ฟ, the claim follows by establishing that ฬ‚๐‘‹๐œƒ,aux,๐‘Žhas uniformly bounded moments of order 4+๐›ฟ. This however holds by Lemma A.14. By the same argument, the processes ฬƒ๐‘‹๐œƒand๐‘‹๐œƒ,homare also bounded in๐ฟ4+๐›ฟ. Sincesupp(๐œ“)โЇ ๐ป has non-empty interior, all ...
https://arxiv.org/abs/2503.05590v1
a geometric rate. Proof. As before let ๐‘Ž๐œƒdenote the state transition vector of ๐‘‹๐œƒand๐‘‹๐œƒ,hom, let๐ด๐œƒ(๐‘ก)and๐ด๐œƒ denote the state transition matrices of ๐‘‹๐œƒand๐‘‹๐œƒ,hom, respectively, and let ๐‘๐œ—denote the martingale difference sequence in the state space representation of ๐‘‹๐œƒand๐‘‹๐œƒ,hom(all under โ„™๐œ—). Then๐‘‹๐œƒ(...
https://arxiv.org/abs/2503.05590v1
Then the Poisson equation ๐‘“(๐‘ฅ) =๐‘ƒ๐œƒ๐‘”(๐‘ฅ)โˆ’๐‘”(๐‘ฅ)+๐‘Ÿis fulfilled whenever ๐›ผโŠค ๐‘”(๐ด๐œƒ โŠ—2โˆ’I) =๐›ผโŠค ๐‘“. This equation has the unique solution ๐›ผโŠค ๐‘”=๐›ผโŠค ๐‘“(๐ด๐œƒ โŠ—2โˆ’I)โˆ’1, where the inverse is well-defined because๐œŒ(๐ด๐œƒ โŠ—2)<1by Remark 5.7. This finishes the proof. The preceding lemma is the main ingredient of the followi...
https://arxiv.org/abs/2503.05590v1
โˆ‘ ๐‘ =1๐‘ˆ๐œ— ๐‘ก(๐‘ )๐‘ˆ๐œ—โŠค ๐‘ก(๐‘ )=1 ๐‘ก๐‘ก โˆ‘ ๐‘ =1[๐‘ƒ๐œ—๐‘”๐œ—(๐‘‹๐œ—,hom(๐‘ โˆ’1))โˆ’๐‘”๐œ—(๐‘‹๐œ—,hom(๐‘ ))][๐‘ƒ๐œ—๐‘”๐œ—(๐‘‹๐œ—,hom(๐‘ โˆ’1))โˆ’๐‘”๐œ—(๐‘‹๐œ—,hom(๐‘ ))]โŠค , where each summand is an โ„๐‘˜ร—๐‘˜-valued random variable whose entries are quartic polynomi- als in๐‘‹๐œ—,hom(๐‘ โˆ’1)and๐‘‹๐œ—,hom(๐‘ ). Since๐‘‹๐œ—,homis weakly๐‘“-ergodic for any quartic polyno...
https://arxiv.org/abs/2503.05590v1
the context of hypothesis testing using the Lagrange Multiplier test, see Section 3.4. This is remedied by a different estimator in Boubacar Ma ยจฤฑnassara [24] and Boubacar Maยจฤฑnassara et al. [25]. Theorem 5.11 establishes the asymptotic normality condition needed in Proposition 5.3, which is taken from Jacod and Sรธrens...
https://arxiv.org/abs/2503.05590v1
or 3.6 and similar algebraic manipulations as in equation (5.21) show for any ๐‘–,๐‘—,๐‘™โˆˆ{1,โ€ฆ,๐‘˜}we have ๐œ•๐œƒ๐‘™๐‘…๐œƒ ๐‘–๐‘—(๐‘ก,๐‘กโˆ’1)=๐น๐œƒ(๐‘กโˆ’1)๐œ•๐œƒ๐‘™๐‘…๐œƒ ๐‘–๐‘—(๐‘ก,๐‘กโˆ’1)๐น๐œƒ(๐‘กโˆ’1)โŠค+terms uniformly bounded in ๐œƒ(5.22) because all third derivatives of ๐ถ๐œƒ(๐‘ก)are uniformly bounded in ๐œƒby Assumption A. Lemma A.10.1 then yields ...
https://arxiv.org/abs/2503.05590v1
in ๐‘กand ๐œƒfor any๐‘™โˆˆ {1,โ€ฆ,๐‘˜}. Since all partial derivatives ๐œ•๐œƒ๐‘™๐”ผ๐œ—[๐‘“(๐‘‹๐œƒ(๐‘ก)) โˆฃ๐‘‹(0) =๐‘ฅ]are uniformly bounded in ๐‘กand๐œƒ, the sequence (๐”ผ๐œ—[๐‘“(๐‘‹๐œƒ(๐‘ก)) โˆฃ๐‘‹(0) =๐‘ฅ])๐‘กโˆˆโ„•โˆ—is equicontinuous by the multivariate mean value theorem, see for example Theorem A.12, and it converges pointwise for๐œ†๐ธ-almost any ๐‘ฅโˆˆ๐ธ,...
https://arxiv.org/abs/2503.05590v1
Simple differen- tiation as in Propositions 3.5 or 3.6 yields that ๐œ•๐œƒ๐‘™๐น๐œƒ(๐‘ก)and๐œ•๐œƒ๐‘™๐บ๐œƒ(๐‘ก)depend on ๐‘กonly through 51 ฬ‚ฮฃ๐œƒ(๐‘ก,๐‘กโˆ’1) and its inverse, ๐‘†๐œƒ ๐‘—(๐‘ก,๐‘กโˆ’1),๐‘…๐œƒ ๐‘–๐‘—(๐‘ก,๐‘กโˆ’1) as well as๐œ•๐œƒ๐‘™๐‘…๐œƒ ๐‘–๐‘—(๐‘ก,๐‘กโˆ’1) for๐‘–,๐‘—,๐‘™โˆˆ{1,โ€ฆ,๐‘˜}. Similar manipulations as in equation (5.21) show ๐œ•๐œƒ๐‘™๐‘…๐œƒ ๐‘–๐‘—(๐‘ก,๐‘ก...
https://arxiv.org/abs/2503.05590v1
Theorem A.20 are fulfilled and we can deduce sup๐œƒโˆˆฮ˜โ€–1 ๐‘กโˆ‘๐‘ก ๐‘ =1๐‘“(๐‘‹๐œƒ(๐‘ ))โˆ’โˆซ๐‘“d๐œ‡๐œƒโ€–โ†’0inโ„™๐œ—-probability. We are now ready to prove the main result of this section, assumed in Proposition 5.2: Proposition 5.16. There exists a continuous matrix-valued function ๐‘Šโˆถ ฮ˜โ†’โ„๐‘˜ร—๐‘˜such that sup๐œƒโˆˆฮ˜โ€–1 ๐‘กโˆ‡๐œƒ๐‘๐œƒ(๐‘ก)โˆ’๐‘Š(๐œƒ)โ€–โ†’0inโ„™...
https://arxiv.org/abs/2503.05590v1
The closed-form expressions for the score process ฬƒ๐‘๐œƒ ๐‘Œ(๐‘ก)and the observed Fisher information โˆ‡๐œƒฬƒ๐‘๐œƒ ๐‘Œ(๐‘ก)are again analogous to the ones given in Propositions 3.5 and 3.6 with ๐ถ๐œƒin place of ๐ถ๐œƒ(๐‘ก). We know that ๐ฟ๐œƒ(๐‘ก,๐‘กโˆ’1)=log๐‘ž๐œƒ ๐‘กโˆฃ๐‘กโˆ’1(๐‘‹o(๐‘ก)โˆฃ๐‘‹o(1),โ€ฆ,๐‘‹o(๐‘กโˆ’1)) is a quadratic polynomial in๐‘‹๐œƒ(๐‘ก)wit...
https://arxiv.org/abs/2503.05590v1
๐‘ก๐‘๐œƒ(๐‘ก), respectively. In view of the uniform convergence to ๐‘Š(๐œƒ)proven in Proposition 5.16, it follows from Lemma A.21 that ๐‘Š(๐œƒ) = โˆ‡๐œƒ๐บ(๐œƒ)as well as ๐บ(๐œƒ) = โˆ‡๐œƒ๐‘„(๐œƒ), and that sup๐œƒโˆˆฮ˜โ€–1 ๐‘ก๐‘๐œƒ(๐‘ก)โˆ’๐บ(๐œƒ)โ€–โ„™๐œ—โˆ’ โˆ’โ†’0as well assup๐œƒโˆˆฮ˜โ€–1 ๐‘ก๐ฟ๐œƒ(๐‘ก)โˆ’๐‘„(๐œƒ)โ€–โ„™๐œ—โˆ’ โˆ’โ†’0. This establishes the uniform convergence propert...
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culminates in the following Azumaโ€“Hoeffding-type inequality for ๐‘Œstat o: Proposition 5.23. Fix๐‘ขโˆˆโ„•โˆ—and๐œƒโˆˆฮ˜and let๐‘“โˆถโ„(๐‘‘โˆ’๐‘š)(๐‘ข+1)โ†’โ„be bounded and measur- able. Then there is a constant ๐พ >0depending on ๐‘ข,๐‘“,๐œƒsuch that we have โ„™๐œƒ(||||1 ๐‘ก๐‘ก โˆ‘ ๐‘ =1๐‘“[๐‘Œstat o(๐‘ ),โ€ฆ๐‘Œstat o(๐‘ +๐‘ข)]โˆ’๐”ผ๐œƒ[๐‘“(๐‘Œstat o(0),โ€ฆ,๐‘Œstat o(๐‘ข)...
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๐œƒ. Since๐‘Œstatis a Gaussian process, Kallsen and Richert [73, Proposition 3.2] yields that the conditional den- sity๐‘“๐‘ โˆฃ๐‘ โˆ’1 ๐œƒ(๐‘ฆ๐‘ โˆฃ๐‘ฆ0,โ€ฆ,๐‘ฆ๐‘ โˆ’1)is the density of the normal distribution with mean ฬ‚๐‘Œ๐œƒ,stat oevaluated at ๐‘Œstat o(0)=๐‘ฆ0,โ€ฆ,๐‘Œstat o(๐‘ โˆ’1)=๐‘ฆ๐‘ โˆ’1and covariance matrix ฬ‚ฮฃ๐œƒ,stat o(๐‘ ,๐‘ โˆ’1) given by the ...
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by ฬ‚๐œƒ(๐‘ก),๐‘Š(ฬ‚๐œƒ(๐‘ก))can be computed explicitly by the calculations in Section 3.3 (if Assumption Aโ€™ holds) in order to verify the invertibility assumption from Theorem 3.4. A large part of the statistical literature on asymptotic normality of (quasi-)maximum like- lihood estimators in hidden Markov models or general ...
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continuity statement in Corollary 5.13. Since (ฬ‚๐œƒ(๐‘ก))๐‘กโˆˆโ„•is๐œ—-consistent, the first claim follows from the continuous mapping theorem. The second follows from Slutskyโ€™s theorem. 61 Proof of Proposition 3.14. For the Wald test statistic, note that sinceโˆš๐‘ก(ฬ‚๐œƒ(๐‘ก)โˆ’๐œ—)โ„™๐œ—-๐‘‘โˆ’ โˆ’โˆ’โ†’๐‘(0,๐‘‰๐œ—), one obtains thatโˆš๐‘ก[๐‘…(ฬ‚๐œƒ(๏ฟฝ...
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Burkholderโ€“Davisโ€“Gundy inequality from Theorem A.22, we obtain โ€–โ€–โ€–โˆซ๐‘ก 0e๐‘„๐‘ d๐ฟ(๐‘ )โ€–โ€–โ€–๐‘ ๐ฟ๐‘โ‰ค๐‘โ€–โ€–โ€–โˆซe๐‘„โ‹…id1[0,๐‘ก]d๐ฟโ€–โ€–โ€–๐‘ ๐ป๐‘โ‰ค๐‘โ€–โ€–e๐‘„โ‹…id1[0,๐‘ก]โ€–โ€–๐‘ ๐‘†โˆžโ€–โ€–๐ฟโ‹…1[0,๐‘ก]โ€–โ€–๐‘ ๐ป๐‘ โ‰ค๐‘(sup ๐‘ โ‰ค๐‘กโ€–โ€–e๐‘„๐‘ โ€–โ€–๐‘ )โ€–โ€–โ€–โ€–[๐‘€๐ฟ,๐‘€๐ฟ](๐‘ก)โ€–1 2+โ€–๐ด๐ฟโ€–(๐‘ก)โ€–โ€–โ€–๐‘ ๐ฟ๐‘ โ‰ค๐‘[๐”ผ(โ€–[๐‘€๐ฟ,๐‘€๐ฟ](๐‘ก)โ€–๐‘ 2)+๐”ผ(โ€–๐ด๐ฟโ€–(๐‘ก)๐‘)] โ‰ค๐‘[๐”ผ(sup ๐‘ โ‰ค๐‘กโ€–๐‘€๐ฟ(๐‘ )โ€–๏ฟฝ...
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transition semigroup (๐‘ƒ๐‘ก)๐‘กโˆˆโ„•, which is connected to ๐‘‹via ๐”ผ(๐‘“(๐‘‹(๐‘ +๐‘ก))|F๐‘ ) = (๐‘ƒ๐‘ก๐‘“)(๐‘‹(๐‘ ))for all๐‘ ,๐‘กโˆˆโ„•and bounded, measurable ๐‘“โˆถ๐ธโ†’โ„. As usual, we use the slightly ambiguous notation ๐‘ƒ๐‘ก(๐‘ฅ,๐ด)โˆถ=(๐‘ƒ๐‘ก1๐ด)(๐‘ฅ)=โ„™๐‘ฅ(๐‘‹(๐‘ก)โˆˆ๐ด)for the๐‘ก- step transition function, where โ„™๐œˆdenotes the measure under which ๐‘‹(0...
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weak Feller chain bounded in probability on average admits an invariant probability measure, see Meyn and Tweedie [85, Theorem 12.1.2(ii)]. Since ๐ธ โІโ„๐‘‘ and any compact set in the relative topology on ๐ธis also compact in โ„๐‘‘, it suffices to show thatlimsup๐‘กโˆˆโ„•โˆ—โ„™๐‘ฅ(โ€–๐‘‹(๐‘ก)โ€–โ‰ฅ๐‘€)converges to 0 as ๐‘€โ†’โˆž. But limsup ๐‘กโ†’โˆžโ„™๏ฟฝ...
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that โ€–๐ดโˆ’1โ€–โˆ’1=๐œŽ๐‘‘. Then โ€–๐ดโˆ’1โ€–=๐œŽโˆ’1 ๐‘‘โ‰ค๐œŽโˆ’1 ๐‘‘(๐‘‘โˆ’1 โˆ ๐‘˜=1๐œŽ1 ๐œŽ๐‘˜)=๐œŽ๐‘‘โˆ’1 1 โˆ๐‘‘ ๐‘˜=1๐œŽ๐‘˜=โ€–๐ดโ€–๐‘‘โˆ’1 |det(๐ด)|. The main content of the following lemmata consists in the fact that powers of a matrix ๐ด converge geometrically fast to 0 whenever its spectral radius ๐œŒ(๐ด)is strictly smaller than 1. This basic result exten...
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particular, ๐ด๐‘šโ†’0at a geometric rate as ๐‘šโ†’โˆž. Alternatively, we can also uniformly bound partial derivatives of chains of differentiable matrix functions by a geometric rate, as the following corollary of Lemma A.7 shows: Corollary A.9. Let๐ธbe a compact subset of โ„๐‘˜and suppose that functions ๐ด๐‘กโˆถ๐ธโ†’โ„๐‘‘ร—๐‘‘and ๐ดโˆถ๐ธโ†’...
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A.5 we obtain the bound โ€–(I๐‘‘โˆ’๐ด(๐‘ฅ))โˆ’1โ€–โ‰คโ€–I๐‘‘โˆ’๐ด(๐‘ฅ)โ€–๐‘‘โˆ’1 |det(I๐‘‘โˆ’๐ด(๐‘ฅ))|. Since the eigenvalues of I๐‘‘โˆ’๐ดare uniformly bounded away from 0, also |det(I๐‘‘โˆ’๐ด)|is uniformly bounded away from 0. Since I๐‘‘โˆ’๐ดis continuous on the compact set ๐ธ, it is bounded and so (I๐‘‘โˆ’๐ด)โˆ’1is also bounded on ๐ธ. Similar to (A.5) we ha...
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Since๐‘‘๐‘–denotes the dimension of each Jordan block ๐ฝ๐‘–, we have๐‘š๐‘˜=๐‘‘for๐‘š๐‘–=๐‘‘1+โ‹ฏ+๐‘‘๐‘–. For any๐‘ฅโˆˆ๐ธ, fix the representation ๐‘ฅ=๐‘˜1(๐‘ฅ)๐‘ฃ1+โ‹ฏ+๐‘˜๐‘‘(๐‘ฅ)๐‘ฃ๐‘‘. Assume now that ๐ดhas some eigenvalue ๐œ†๐‘–with|๐œ†๐‘–|โ‰ฅ1. Since the map ๐ด๐‘›is given by ๐ฝ๐‘›with respect to the basis ๐‘‰, it follows that the components ๐‘š๐‘–โˆ’1+1,โ€ฆ...
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for |||๐‘€+๐‘|||โ‰ 0: |||๐‘€+๐‘|||๐‘=๐”ผ[sup ๐‘ฅโˆˆ๐ธโ€–๐‘€๐‘ฅ+๐‘๐‘ฅโ€–๐‘]=๐”ผ[sup ๐‘ฅโˆˆ๐ธ(โ€–๐‘€๐‘ฅ+๐‘๐‘ฅโ€–โ‹…โ€–๐‘€๐‘ฅ+๐‘๐‘ฅโ€–๐‘โˆ’1)] โ‰ค๐”ผ[sup ๐‘ฅโˆˆ๐ธ(โ€–๐‘€๐‘ฅโ€–sup ๐‘ฅโˆˆ๐ธโ€–๐‘€๐‘ฅ+๐‘๐‘ฅโ€–๐‘โˆ’1)]+๐”ผ[sup ๐‘ฅโˆˆ๐ธ(โ€–๐‘๐‘ฅโ€–sup ๐‘ฅโˆˆ๐ธโ€–๐‘€๐‘ฅ+๐‘๐‘ฅโ€–๐‘โˆ’1)] โ‰ค(๐”ผ[sup ๐‘ฅโˆˆ๐ธโ€–๐‘€๐‘ฅโ€–๐‘]1 ๐‘+๐”ผ[sup ๐‘ฅโˆˆ๐ธโ€–๐‘๐‘ฅโ€–๐‘]1 ๐‘ )๐”ผ[(sup ๐‘ฅโˆˆ๐ธโ€–๐‘€๐‘ฅ+๐‘๐‘ฅโ€–๐‘โˆ’1)๐‘ ๐‘โˆ’1 ]๐‘โˆ’1 ๐‘ =(|||๐‘€|||+|||๐‘|||)|||...
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we can assume that ๐‘˜= 1. Let the function ๐‘”โˆถโ„๐‘‘โ†’โ„be again of the form ๐‘”(๐‘ฅ) =โˆ‘|๐œ†|โ‰ค๐‘ž๐›ผ๐œ†๐‘ฅ๐œ† As in the proof of Lemma A.16, we have โ€–๐‘”(๐‘‹(๐‘ก))โˆ’๐‘”(๐‘Œ(๐‘ก))โ€–โ€–๐‘ ๐‘žโ‰คโˆ‘|๐œ†|โ‰ค๐‘ž|๐›ผ๐œ†|โ€–๐‘‹(๐‘ก)๐œ†โˆ’๐‘Œ(๐‘ก)๐œ†โ€–๐‘ ๐‘ž; so it suffices the show the claim for monomials ๐‘”(๐‘ฅ)=๐‘ฅ๐œ†with|๐œ†|โ‰ฅ1. Now ๐‘‹(๐‘ก)๐œ†โˆ’๐‘Œ(๐‘ก)๐œ†=๐‘‘ โˆ ๐‘—=1๐‘‹๐‘—(๐‘ก)๐œ†๐‘—...
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๐‘˜|โ‰คโ€–๐‘กโ€–โ€–๐‘ˆ(๐‘›) ๐‘˜โ€–by the Cauchyโ€“Schwarz inequality, we have ๐‘˜๐‘› โˆ‘ ๐‘˜=1๐”ผ[|๐‘กโŠค๐‘ˆ(๐‘›) ๐‘›|21{|๐‘กโŠค๐‘ˆ(๐‘›) ๐‘˜|>๐œ€}]โ‰คโ€–๐‘กโ€–2๐‘˜๐‘› โˆ‘ ๐‘˜=1๐”ผ[โ€–๐‘ˆ(๐‘›) ๐‘˜โ€–21{โ€–๐‘ˆ(๐‘›) ๐‘˜โ€–โ‰ฅ๐œ€ โ€–๐‘กโ€–}]๐‘›โ†’โˆžโˆ’ โˆ’โˆ’โ†’0 by 2. Thus, the array ๐‘กโŠค๐‘ˆ(๐‘›) ๐‘˜fulfils the conditions 1. and 2. in the case ๐‘‘= 1, whence ๐‘กโŠค๐‘€๐‘›๐‘‘โˆ’โ†’๐‘กโŠค๐‘. By the Cram ยดerโ€“Wold theorem we ...
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for each ๐‘ฅโˆˆ๐ธa sequence of๐‘‘-dimensional random variables (๐‘Œ๐‘ฅ(๐‘ก))๐‘กโˆˆโ„•โˆ—as well as a deterministic ๐‘Œ(๐‘ฅ)โˆˆโ„๐‘‘are given such that๐‘Œ๐‘ฅ(๐‘ก)and๐‘Œ(๐‘ฅ)are continuous in ๐‘ฅ. Suppose moreover that ๐‘Œ๐‘ฅ(๐‘ก)โ„™โˆ’โ†’๐‘Œ(๐‘ฅ)for each๐‘ฅโˆˆ๐ธand that for each ๐‘ฅโˆˆ๐ธthe uniform stochastic equicontinuity condition lim ๐›ผโ†’0limsup ๐‘กโ†’โˆžโ„™(sup ๐‘‘(...
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less than๐œ€ 3for some large enough ๐‘กindependent of ๐‘ฅandโ„Ž, while the term ๐ตbecomes less than๐œ€ 3for any fixed ๐‘กif|โ„Ž|is small enough. It follows that ๐œ•๐‘ฅ๐‘—๐‘Œ(๐‘ฅ)๐‘–=๐‘Š(๐‘ฅ)๐‘–๐‘—. In Section 4.2 we need multivariate extensions of the well-known Burkholderโ€“Davisโ€“Gun- dy inequality (see Dellacherie and Meyer [36, Theorem ...
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โ„๐‘šร—๐‘›-valued process and ๐‘‹anโ„๐‘›-valued semi- martingale. Moreover, let1 ๐‘+1 ๐‘ž=1 ๐‘Ÿfor1โ‰ค๐‘โ‰คโˆžand1โ‰ค๐‘žโ‰คโˆž. Then โ€–โ€–โ€–โˆซ๐ปd๐‘‹โ€–โ€–โ€–๐ป๐‘Ÿโ‰ค๐‘›โˆš๐‘šโ€–๐ปโ€–๐‘†๐‘โ€–๐‘‹โˆ’๐‘‹(0)โ€–๐ป๐‘ž. Proof. Fix a semimartingale decomposition ๐‘‹=๐‘‹(0)+๐‘€+๐ด. Thenโˆซ๐ปd๐‘‹=โˆซ๐ปd๐‘€+ โˆซ๐ปd๐ดis a decomposition for โˆซ๐ปd๐‘€. Recall that [โˆซ๐ปd๐‘€,โˆซ๐ปd๐‘€] =โˆซ๐ปd[๐‘€,๐‘€]๐ปโŠค. We w...
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Ornsteinโ€“Uhlen- beck process for electricity spot price modelling and derivatives pricing. In: Applied Mathematical Finance 14.2, pp. 153โ€“169. [17] F. E. Benth and S. Lavagnini (2021). Correlators of polynomial processes. In: SIAM Journal on Financial Mathematics 12.4, pp. 1374โ€“1415. [18] D. S. Bernstein (2011). Matrix...
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and R. Van Handel (2011). Consistency of the Maxi- mum Likelihood estimator for general hidden Markov models. In: The Annals of Statis- tics39.1, pp. 474โ€“513. [39] G. R. Duffee (2002). Term premia and interest rate forecasts in affine models. In: The Journal of Finance 57.1, pp. 405โ€“443. [40] D. Duffie, D. Filipovi ยดc,...
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I. Gordin and B. A. Lif ห‡sic (1978). Central limit theorem for stationary Markov pro- cesses. In: Dokladi Akademii Nauk SSSR 239.4, pp. 766โ€“767. [61] J. J. Green (1996). Uniform Convergence to the Spectral Radius and Some Related Prop- erties in Banach Algebras. Doctoral thesis, University of Sheffield. [62] P. Hall an...
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variables. In: Computational Statistics and Data Analysis 53.4, pp. 853โ€“856. [81] R. Lord, R. Koekkoek, and D. J. C. van Dijk (2010). A comparison of biased simulation schemes for stochastic volatility models. In: Quantitative Finance 10.2, pp. 177โ€“194. [82] K. W. Lu (2022). Calibration for multivariate L ยดevy-driven O...
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Fields 151.1, pp. 173โ€“190. [103] K. Singleton (2001). Estimation of affine asset pricing models using the empirical char- acteristic function. In: Journal of Econometrics 252.1-3, pp. 61โ€“70. [104] M. Sรธrensen (2012). Estimating functions for diffusion-type processes. In: M. Kessler, A. Lindner, M. Sรธrensen (Eds.), Stat...
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arXiv:2503.05880v1 [math.ST] 14 Feb 2025Asymptotic properties of maximum composite likelihood est imators for max-stable Brown-Resnick random ๏ฌelds over a ๏ฌxed-domain Nicolas CHENAVIERโˆ—and Christian Y. ROBERTโ€  March 11, 2025 Abstract Likelihoodinferenceformax-stablerandom๏ฌeldsisingeneralimposs iblebecausetheir๏ฌnite-dim...
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be distinguished: microergodic and non-microergodic parameters. A parameter is said to be microergo dic if, for two di๏ฌ€erent values of it, the two corresponding Gaussian measures are orthogonal [ 25,33]). It is non-microergodic if, even for two di๏ฌ€erent values of it, the two corresponding Gaussian measure s are equival...
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instead of Xunder a ๏ฌxed-domain framework. They established that the asymptotic distribution theory for nona๏ฌƒne gis somewhat richer than in the Gaussian case (i.e. whengis an a๏ฌƒne transformation). Although the variogram-based estima tors are not MLE or MCLE, this study shows that their asymptotic properties can di๏ฌ€er s...
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this paper, we consider the classof spatial max-stableBrown-R esnickrandom๏ฌelds ( d= 2) associated with isotropic fractional Brownian random ๏ฌelds as de๏ฌned in [ 27]. Because the sites where the random ๏ฌelds are observed are very rarely on grids in practice, we consider ed a random sampling scheme. We assume a Poisson ...
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(see Theorem 2 in [ 9]). In this paper we generalize this result to the max-stable Brown-R esnick random ๏ฌeld which is built as the pointwise maximum of an in๏ฌnite number of isotro pic fractional Brownian ๏ฌelds (see Theorem 3). Using approximations of the pairwise and triplewise CL objective fu nctions, we then derive ...
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has the following form Y(x) = exp(W(x)โˆ’ฮณ(x)), xโˆˆR2, (2.2) whereWis an isotropic fractional Brownian ๏ฌeld. With this choice, the max-st able random ๏ฌeld ฮทis stationary while Wis not but has (linear) stationary increments (see [ 27]). 2.2 Delaunay triangulation In this section, we recall some known results on Poisson-Del...
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( x1,x2) such that the following conditions hold: x1โˆผx2in Del(PN), x1โˆˆB,andx1/โˆšrecedesequalx2, where/โˆšrecedesequaldenotes the lexicographic order. When B=C, we simply write EN,C=EN. For a Borel subsetBinR2, letDTN,Bbe the set of triples ( x1,x2,x3) satisfying the following properties โˆ†(x1,x2,x3)โˆˆDel(PN), x1โˆˆB,andx1/โˆšre...
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not a surprise since the probability that x1andx2belong to the same cell of the canonical tessellation ofthe max-stablerandom๏ฌeld tends to 1. Indeed, in a commoncell, t he valuesof the max-stablerandom ๏ฌeld are generated by the same isotropic fractional Brownian rand om ๏ฌeld. 3.1.2 Pairs of increments Let us now consid...
https://arxiv.org/abs/2503.05880v1
fV(ฮท) 2,NandV(ฮท) 3,N. Theorem 3 Letฮฑโˆˆ(0,1). Then, as Nโ†’ โˆž, โˆš 3 3Nโˆ’(2โˆ’ฮฑ)/4V(ฮท) 2,NPโ†’cV2/summationdisplay jโ‰ฅ1/summationdisplay k>jLZk\j(0) โˆš 2 2Nโˆ’(2โˆ’ฮฑ)/4V(ฮท) 3,NPโ†’cV3/summationdisplay jโ‰ฅ1/summationdisplay k>jLZk\j(0). In the above theorem we have assumed that ฮฑโˆˆ(0,1) whereas, in general, ฮฑโˆˆ(0,2). Such an assumption is im...
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and explain how we de๏ฌne the MCLEs for the other paramete r. 12 Whenฮฑ0is assumed to be known, the pairwise and triplewise maximum (tapered ) CL estimators of ฯƒ0, denoted by ห† ฯƒj,N, are respectively de๏ฌned as a solution of the maximization problems max ฯƒโˆˆSฯƒโ„“j,N(ฯƒ,ฮฑ0), j= 2,3. Whenฯƒ0is assumed to be known, the pairwise a...
https://arxiv.org/abs/2503.05880v1
o fฯƒ2 0andฮฑ0(when the other parameter is known) are consistent in our in๏ฌll asymptotic setup. T hey have rates of convergence pro- portional to Nฮฑ0/4for ห†ฯƒ2 2,Nand log(N)Nฮฑ0/4for ห†ฮฑ2,Nthat di๏ฌ€er from the expected ratesof convergence N1/2and log(N)N1/2as in [35] for the isotropic fractional Brownian ๏ฌeld. Second the typ...
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is given in ( 2.1). SinceW(x2โˆ’x1)โˆผ N(0,2ฮณ(x2โˆ’x1)) and since 2 ฮณ(x2โˆ’x1) = ฯƒ2||x2โˆ’x1||ฮฑ=ฯƒ2dฮฑ, we deduce that E/bracketleftbigg I/bracketleftbiggY(x2โˆ’x1) z2โ‰คY(0) z1/bracketrightbigg Y(0)/bracketrightbigg = ฮฆ/parenleftbigg ฯƒโˆ’1dโˆ’ฮฑ/2log/parenleftbiggz2 z1/parenrightbigg +1 2ฯƒdฮฑ/2/parenrightbigg = ฮฆ/parenleftbigg u+1 2ฯƒdฮฑ/2/p...
https://arxiv.org/abs/2503.05880v1
V(ฮท) 2,N LetH2(u) :=u2โˆ’1 be the Hermite polynomial of degree 2 so that V(ฮท) 2,N=1/radicalbig |EN|/summationdisplay (x1,x2)โˆˆENH2/parenleftBig U(ฮท) x1,x2/parenrightBig . To deal with the right-hand side, we write H2(U(ฮท) x1,x2) =H2/parenleftBigg U(ฮท) x1,x2+ฮณ(x2)โˆ’ฮณ(x1) ฯƒ/bardblx2โˆ’x1/bardblฮฑ/2/parenrightBigg โˆ’2U(ฮท) x1,x2ฮณ(...
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0,ฯƒ2 V2/parenrightbig . To deal with the second term, we consider the tessellation ( Ck,j)k/\egatio\slash=jโ‰ฅ1, whereCk,jโŠ‚Cis de๏ฌned in Eq. (3.5). Notice also that the set JC={(k,j) :Ck,j/ne}ationslash=โˆ…}is a.s. ๏ฌnite. Adapting the proof of Proposition 1 in [9], we can prove that, for any ( k,j)โˆˆ JC, โˆš 3 3Nโˆ’(2โˆ’ฮฑ)/41/rad...
https://arxiv.org/abs/2503.05880v1
ฯƒ/bardblx3โˆ’x1/bardblฮฑ/2 and N(3) x1,x2,x3=/summationdisplay jโ‰ฅ1/summationdisplay k/\egatio\slash=jI๏ฃฎ ๏ฃฐ/logicalordisplay iโ‰ฅ1Zi(x1) =Zj(x1),/logicalordisplay iโ‰ฅ1Zi(x2) =Zk(x2),x1orx2/โˆˆCk,j๏ฃน ๏ฃป ร—U(Wj) x1,x2 ฯƒ/bardblx3โˆ’x1/bardblฮฑ/2Zk\j(x1) +/summationdisplay jโ‰ฅ1/summationdisplay k/\egatio\slash=jI๏ฃฎ ๏ฃฐ/logicalordisplay iโ‰ฅ1Zi(...
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1+a 2u+o(a)/parenrightBig . 26 We deal below with each term of Eq. ( 5.4). First, we notice that ฯ•(v(u))v(โˆ’u) =ฯ•(u)/parenleftBig 1โˆ’a 2u+o(a)/parenrightBig/parenleftBiga 2โˆ’u/parenrightBig +o(a) =โˆ’uฯ•(u)/parenleftBig 1โˆ’a 2/parenleftbig u+uโˆ’1/parenrightbig +o(a)/parenrightBig +o(a) and that eโˆ’auฯ•(v(โˆ’u))v(u) = (1 โˆ’au+o(a))ฯ•...
https://arxiv.org/abs/2503.05880v1
1R1 R11/parenrightBiggโˆ’1/parenleftBigg v1,2(u1,2) v1,3(u1,3)/parenrightBigg . Sinceโˆ‚ โˆ‚ฯƒvi,j(ui,j) =1 ฯƒvi,j(โˆ’ui,j) andโˆ‚ โˆ‚ฯƒai,j=1 ฯƒai,j, 29 we deduce that ฯƒโˆ‚ โˆ‚ฯƒlog/parenleftbigg โˆ’โˆ‚3 โˆ‚z1โˆ‚z2โˆ‚z3Vx1,x2,x3(z1,z2,z3)/parenrightbigg =โˆ’a1,2u1,2โˆ’a1,3u1,3โˆ’2โˆ’1 1โˆ’R2 1(v1,2(u1,2)โˆ’R1v1,3(u1,3))v1,2(โˆ’u1,2) โˆ’1 1โˆ’R2 1(v1,3(u1,3)โˆ’R1v1,2(u...
https://arxiv.org/abs/2503.05880v1
to Proposition 8) 1 |EN|/summationdisplay (x1,x2)โˆˆENk0/summationdisplay k=0k/summationdisplay j=0|U(ฮท) x1,x2|j/bardblx2โˆ’x1/bardbl(k+1โˆ’j)ฮฑ/2Pโ†’0, and1 |EN|/summationdisplay (x1,x2)โˆˆEN(U(ฮท) x1,x2)2Pโ†’1, we deduce that |ห†ฮฑ2,Nโˆ’ฮฑ|logNPโ†’0. From Eq. ( 5.5), we have /parenleftbigg 1+1 2(ห†ฮฑ2,Nโˆ’ฮฑ)logN(1+oP(1)/parenrightbigg1 |EN|/...
https://arxiv.org/abs/2503.05880v1
for large kth-nearest neighbor balls. J. Appl. Probab., 59(3):880โ€“894, 2022. [8] N. Chenavier and C. Y. Robert. Central limit theorems for squar ed increment sums of fractional Brownian ๏ฌelds based on a Delaunay triangulation in 2 D.WP, 2025. [9] N. Chenavier and C. Y. Robert. Limit theorems for squared incre ment sums...
https://arxiv.org/abs/2503.05880v1
Detecting correlation efficiently in stochastic block models: breaking Otterโ€™s threshold by counting decorated trees Guanyi Chenโˆ—Jian Dingโ€ Shuyang Gongโ€กZhangsong Liยง March 11, 2025 Abstract Consider a pair of sparse correlated stochastic block models S(n,ฮป n, ฯต;s) subsampled from a common parent stochastic block model ...
https://arxiv.org/abs/2503.06464v1
J. Ding is partially supported by the National Key R&D program of China (No. 2023YFA1010103), the NSFC Key Program (No. 12231002) and the Now Cornerstone Science Foundation through the XPLORER PRIZE. โ€กPeking University. Part of the work was carried out when S. Gong was visiting Duke University. S. Gong would like to th...
https://arxiv.org/abs/2503.06464v1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 C.7 Proof of Lemma 5.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 C.8 Proof of Lemma C.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 C.9 Proof of Lemma C.4 . . . . . . . . . . . . . . . . . . ...
https://arxiv.org/abs/2503.06464v1
algorithms were proposed when the correlation exceeds an arbitrarily small constant [DL22+, DL23+]. The separation between the sparse and dense regimes above, roughly speaking, depends on whether the average degree grows polynomially or sub-polynomially. In addition, another important direction is to establish lower bo...
https://arxiv.org/abs/2503.06464v1
is to study the following hypothesis testing problem: determine whether ( A, B) is sampled from PnorQn, where Qnis the distribution of two independent stochastic block models S(n,ฮปs n, ฯต). In our previous work [CDGL24+] (where we considered symmetric SBMs with kcommunities for kโ‰ฅ2), we considered the problem of testing...
https://arxiv.org/abs/2503.06464v1
1.5. In [CR24], the authors seem to tend to feel that in the logarithmic degree regime the correlated SBMs belong to the same algorithmic universality class of sparse correlated Erdห os-Rยด enyi model, and thus all inference tasks are computationally impossible when s <โˆšฮฑ. However, our result suggests a different possib...
https://arxiv.org/abs/2503.06464v1
detection threshold is stillโˆšฮฑ. However, as shown in Theorem 1.3, we show that in the very supercritical regime (i.e., when the signal strength of community is sufficiently large), the correlation detection threshold is indeed influenced by the community structure and thus is strictly below Otterโ€™s threshold. Intuitive...
https://arxiv.org/abs/2503.06464v1
marginally both AandBare Erdห os-Rยด enyi graphs G(n,ฮปs n) and their edge correlation is given by Cov( Aฯ€โˆ—(i),ฯ€โˆ—(j), Bi,j) = [1+ o(1)]s. A natural attempt is to count the (centered) graphs Hin both AandBfor each unlabeled graph H, i.e., we consider the statistics gH=X Sโˆผ=HY (i,j)โˆˆE(S)(Ai,jโˆ’ฮปs n)X Kโˆผ=HY (i,j)โˆˆE(K)(Bi,...
https://arxiv.org/abs/2503.06464v1
combine the subgraph counts relevant to both tasks. To be more precise, our approach involves counting a carefully chosen family of unlabeled multigraphs, which (informally speaking) is formed by attaching non-backtracking paths to an unlabeled tree; the flexibility to choose the place of attachment enrich the enumerat...
https://arxiv.org/abs/2503.06464v1
edge set of H. We say His a subgraph of G, denoted by HโŠ‚G, ifV(H)โŠ‚V(G) and E(H)โŠ‚E(G). We sayฯ†:V(H)โ†’V(S) is an injection, if for all ( i, j)โˆˆE(H) we have ( ฯ†(i), ฯ†(j))โˆˆE(S). ForH, SโŠ‚ K n, denote by HโˆฉSthe graph with vertex set given by V(H)โˆฉV(S) and edge set given by E(H)โˆฉE(S), and denote by SโˆชHthe graph with vertex set...
https://arxiv.org/abs/2503.06464v1
and has no cycles. We say a pair ( T,R(T)) is a rooted tree with root R(T), ifTis a tree and R(T)โˆˆV(T). For a rooted tree TanduโˆˆV(T), we define DepT(u) =Dist T(R(T), u) to be 8 the depth of uinT. For u, vโˆˆV(T), denote by uโ†’v(or equivalently, vโ†u) ifvis the children of u, and denote by u ,โ†’v(or equivalently, vโ†- u) ifvi...
https://arxiv.org/abs/2503.06464v1
to choose ฮด,โˆ† in Theorem 1.3 and make several assumptions on various auxiliary parameters that will be used throughout the paper. To this end, we first need the following results on several enumeration problems regarding unlabeled trees which were established in [Ott48]. 9 Lemma 2.1. Denote VNas the set of unlabeled tr...
https://arxiv.org/abs/2503.06464v1
and the red vertices constitute the pairing P(H); right: example of a multigraph SโŠฉAHwhere the yellow parts are the self-avoiding paths attached to T(S). Given S1โŠฉAH, S2โŠฉBHwhere His a decorated tree, we may write ฯ•S1,S2(A, B) =ฯ•S1(A)ฯ•S2(B), where for SโŠฉH ฯ•S(X) =Y (i,j)โˆˆE(T(S))Xi,jโˆ’ฮปs nq ฮปs n(1โˆ’ฮปs n)ยทฮนโ„ตY k=1Y (i,j)โˆˆE(Lk...
https://arxiv.org/abs/2503.06464v1
as incorporated in the following lemma. Lemma 2.9. For each Tโˆˆ Tโ„ต, define S(T) ={W1, . . . , W M}where W1, . . . , W Mare given as in Theorem 2.8. Define H=H(ฮน,โ„ต, โ„“, M ;Tโ„ต,S(Tโ„ต)). We then have |H| โ‰ฅ ฮฑโˆ’1exp ฮน(log log( ฮนโˆ’1))4โ„ต . Proof. The result of Lemma 2.9 follows directly from Theorems 2.7 and 2.8. We now describ...
https://arxiv.org/abs/2503.06464v1
we have uฬธโˆˆV(T(S))\ L(T(S)). This suggests that L(eS)โŠ‚ L(T(S)). We now show that L(eS) =L(S). Clearly we have L(S)โŠ‚ L(eS). In addition, for all uโˆˆ L(eS)โŠ‚ L(T(S)), denote ( u, v) to be the edge in T(S). For all 1 โ‰คiโ‰คฮนโ„ต, we must have uฬธโˆˆV(Li(S))\ EndP( Li(S)) since otherwise the degree of uineSis at least 2. This suggest...
https://arxiv.org/abs/2503.06464v1
bit more about the construction of our statistic f(A, B) and the seemingly daunting choices of Tโ„ต,S(Tโ„ต). Recall that we are in the supercritical region ฯต2ฮปs > 1 where weak community recovery in Aand Bis possible. Also, assuming that all the community labelings in AandB(we denote them as ฯƒA andฯƒB) are known to us, it is...
https://arxiv.org/abs/2503.06464v1
the baseline as (non-rigorously speaking) the enumeration of such graphs depends on the number of vertices of Gโˆชand the expectation in each case depends on the number of edges of Gโˆช. โ€ขIf the two trees T(K1),T(K2) (or T(S1),T(S2)) do not completely overlap (see Figure 2(c)), there will also be additional cycles and thus...
https://arxiv.org/abs/2503.06464v1
(i,j)โˆˆE(S1)โˆชE(S2)max uฯ‡1(i,j),ฯ‡2(i,j), vฯ‡1(i,j),ฯ‡2(i,j) . (3.8) Lemma 3.6. Given a tree Tand a subset UโŠ‚V(T)such that Dist T(u,v)โ‰ฅdfor all u,vโˆˆU (uฬธ=v), we have Eh ฯ•T(A)2ยทY uโˆˆUฯƒui โ‰ค2|U|ยทฯตd|U|/2. (3.9) 18 The proofs of Lemmas 3.4, 3.5 and 3.6 are incorporated in Sections C.3, C.4 and C.5 of the appendix, respectively. ...
https://arxiv.org/abs/2503.06464v1
Plugging (3.17) into (3.15) yields the desired lower bound for EPid[fA]. For the upper bound, recall that for all S1, S2โˆˆRโˆ— Hsuch that idโˆˆ A(S1, S2), we have S1โˆฉS2is a tree containing T(S1)โˆชT(S2). Thus, denoting P(S1) ={(u1, u2), . . . , (u2ฮนโ„ตโˆ’1, u2ฮนโ„ต)}, there must exist paths L1, . . . ,L2ฮนโ„ตwith uiโˆˆEndP( Li) such that...
https://arxiv.org/abs/2503.06464v1
Using Lemmas 3.2 and 3.5 (with V=โˆ…), we see that (3.23) is bounded by (below we denote E(S)i,j= 0 if ( i, j)ฬธโˆˆE(S)) 25ฯ„(Gโˆช)+10โ„ตY (i,j)โˆˆE(Gโˆช)โˆšnโˆš ฯต2ฮปsE(S1)i,j+E(S2)i,jโˆ’2 . Using the fact that X (i,j)โˆˆE(Gโˆช)(E(S1)i,j+E(S2)i,jโˆ’2) = 2( โ„ต โˆ’1 +ฮนโ„“โ„ต)โˆ’2|E(Gโˆช)|, we obtain that (3.23) is further bounded by 25ฯ„(Gโˆช)+10โ„ตnโ„ตโˆ’1+ฮนโ„“โ„ตโˆ’|E(...
https://arxiv.org/abs/2503.06464v1
โ‰ค |E(eS1)|+|E(eS2)| โ‰ค2โ„“ฮนโ„ต+ 2โ„ต, we obtain ฯ„(Gโˆช)โˆ’|E(Gโˆช)| โ„“/2= ฯ„(Gโˆช)โˆ’|E(Gโˆช)|โˆ’โ„ต โ„“ โˆ’|E(Gโˆช)|+โ„ต โ„“ โ‰ฅ โˆ’2โ„ต โ„“โˆ’2โ„“ฮนโ„ต+2โ„ต โ„“=โˆ’2ฮนโ„ต โˆ’4โ„ต โ„“, as desired. We can now complete the proof of Lemma 3.9. Proof of Lemma 3.9. Based on Lemma 3.10, we have (in what follows we say Gsatisfies (3.27) if (3.27) holds after replacing GโˆชbyGand we denote...
https://arxiv.org/abs/2503.06464v1
T(H))2 n2(โ„ต+โ„“ฮนโ„ต)X (S,K)โˆˆPHEQ[ฯ•S(A)ฯ•K(A)]2 (4.10) +X H,IโˆˆHs2(โ„ตโˆ’1)(ฯต2ฮปs)2โ„“ฮนโ„ตAut( T(H)) Aut( T(I)) n2(โ„ต+โ„“ฮนโ„ต)X (S,K)โˆˆQH,IEQ[ฯ•S(A)ฯ•K(A)]2 . (4.11) We first control (4.10). Note that for ( S, K)โˆˆPH, there exist self-avoiding paths {Lu:uโˆˆ Vert(P(S))}satisfying uโˆˆEndP( Lu) for all uโˆˆVert(P(S)) such that SโˆฉK=T(S)โŠ•(โŠ•uโˆˆVert(P...
https://arxiv.org/abs/2503.06464v1
all (S, K)ฬธโˆˆPโˆ— H,Isuch that eSโˆชeK=GโˆชandL(S)โˆชL(K)โŠ‚V(SโˆฉK), we have 2ฮนโ„ต โˆ’ฯ„(Gโˆช)โ‰ค2โ„“ฮนโ„ต+2โ„ตโˆ’|E(Gโˆช)| โ„“/2. (4.16) Proof. The proof is highly similar to the proof of Lemma 3.10, and we omit further details here for simplicity. Using Lemma 4.3, we have X S,KฬธโˆˆPโˆ— H,IEQ[ฯ•S(A)ฯ•K(A)]โ‰คX |E(Gโˆช)|โ‰ค2โ„“ฮนโ„ต+2โ„ต Gโˆชsatisfies (4.16)X SโˆชK=GโˆชEQ[ฯ•S(A...
https://arxiv.org/abs/2503.06464v1
Gโ‰ฅ2 contains T(K1) and the other contains T(K2). In conclusion, when ( S1, S2, K1, K2)โˆˆRโˆ— H,Iand idโˆˆ A โ‹†(S1, S2;K1, K2) one of the two following conditions must hold: (i) S1โˆฉS2, K1โˆฉK2are two 32 disjoint trees containing T(S1)โˆชT(S2),T(K1)โˆชT(K2) respectively; (ii) S1โˆฉK2, K1โˆฉS2are two disjoint trees containing T(S1)โˆชT(K2)...
https://arxiv.org/abs/2503.06464v1
paths. The proof is similar and we omit further details. Proof of Lemma 4.5. Define GT=Gโ‰ฅ2โˆชT(S1)โˆชT(S2)โˆชT(K1)โˆชT(K2). Note that we have assumed L(Gโˆช)โŠ‚V(Gโ‰ฅ2). Define ฮ“ to be the number of elements in {Li(S1),Li(S2),Li(K1),Li(K2) : 1โ‰คiโ‰คฮนโ„ต} that are included in GT. It is straightforward to check that ฯ„(Gโˆช)โˆ’ฯ„(GT)โ‰ฅ4ฮนโ„ตโˆ’ฮ“ and |...
https://arxiv.org/abs/2503.06464v1
. , Mฮนโ„ต(S)such that the following conditions hold: (1)V(T(S))โŠ‚[n]\ JA; (2)EndP( Mi(S)) ={ui, vi}where ui, viโˆˆV(T(S))and the neighbors of ui, viinMi(S)are in JA; (3) Denoting P(S) ={(u1, v1), . . . , (uฮนโ„ต, vฮนโ„ต)}, there exists a graph isomorphism ฯ†:Sโ†’Hsuch thatฯ†maps T(S)toT(H),maps P(S)toP(H)and maps Mk(S)toMk(H)for1โ‰คkโ‰คฮน...
https://arxiv.org/abs/2503.06464v1