diff --git "a/_NFST4oBgHgl3EQfdDhQ/content/tmp_files/load_file.txt" "b/_NFST4oBgHgl3EQfdDhQ/content/tmp_files/load_file.txt" new file mode 100644--- /dev/null +++ "b/_NFST4oBgHgl3EQfdDhQ/content/tmp_files/load_file.txt" @@ -0,0 +1,789 @@ +filepath=/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf,len=788 +page_content='arXiv:2301.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='13805v1 [math.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='PR] 31 Jan 2023 PARABOLIC EQUATIONS AND SDES WITH TIME-INHOMOGENEOUS MORREY DRIFT D.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' KINZEBULATOV Abstract.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' We prove the unique weak solvability of stochastic differential equations with time- inhomogeneous drift in essentially the largest (scaling-invariant) Morrey class, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' with integra- bility parameter q > 1 close to 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The constructed weak solutions constitute a Feller evolution family.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The proofs are based on a detailed Sobolev regularity theory of the corresponding parabolic equation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Introduction 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' We consider the problem of weak well-posedness of stochastic differential equation Xt = x − � t 0 b(r, Xr)dr + √ 2Bt, x ∈ Rd, (1) where Bt is a Brownian motion in Rd, under minimal assumptions on the time-inhomogeneous vector field b : R × Rd → Rd (drift), d ≥ 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' This equation or, more generally, stochastic equations additionally having variable, possibly discontinuous diffusion coefficients, arise e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' in the problems of stochastic optimization and serve as a basis for many physical models.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' This requires, generally speaking, dealing with irregular, locally unbounded drifts.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' An illustrative example is equation (1) with velocity field b obtained by solving 3D Navier-Stokes equations, which models the motion of a small particle in a turbulent flow [26].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' One is thus led to the problem of establishing weak and strong well-posedness of (1) under minimal assumptions on b.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The latter can also be stated as the problem of finding the most general integral characteristics of b that determine whether (1) is weakly/strongly well-posed.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Let us give a brief outline of the literature on stochastic differential equations (SDEs) with singular drift.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' We will try to keep the chronological order, but will be somewhat loose with the terminology by including in “well-posedness” the uniqueness results of different strength.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The “sub-critical” Ladyzhenskaya-Prodi-Serrin class |b| ∈ Ll(R, Lp(Rd)), p ≥ d, l ≥ 2, d p + 2 l < 1 (2) was attained by Portenko [28] (weak solutions) and Krylov-Röckner [25] (strong solutions).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' See also Zhang [34, 35, 36].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Between [28] and [25], Bass-Chen [3] proved existence and uniqueness 2010 Mathematics Subject Classification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' 60H10, 47D07 (primary), 35J75 (secondary).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Key words and phrases.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Stochastic differential equations, weak solutions, singular drifts, Morrey class, Feller property.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The research of the author is supported by the NSERC (grant RGPIN-2017-05567).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' 1 2 D.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' KINZEBULATOV in law of weak solutions of (1) for b = b(x) in the Kato class of vector fields.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The Kato class contains {|b| ∈ Lp(Rd), p > d} as well as some vector fields with entries not even in L1+ε loc (Rd), ε > 0, however, it does not contain {|b| ∈ Ld(Rd)}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Speaking of time-homogeneous drifts, of course, the fact that p = d is the optimal exponent on the scale of Lebesgue spaces can be seen from rescaling the parabolic equation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In [4], Beck-Flandoli-Gubinelli-Maurelli developed an approach to proving strong well-posedness of (1) with b in the critical Ladyzhenskaya-Prodi-Serrin class |b| ∈ Ll(R, Lp(Rd)), p ≥ d, l ≥ 2, d p + 2 l ≤ 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' (3) for a.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' starting point x ∈ Rd via stochastic transport and stochastic continuity equations.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' They also considered the following example.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Let b(x) = √ δ d − 2 2 1|x|<1|x|−2x, (4) so |b| just misses to be Ld(Rd).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' If δ > 4( d d−2)2, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' the attraction to the origin by the drift is large enough, then SDE (1) with the starting point x = 0 does not have a weak solution.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In [15], Semënov and the author showed that the Feller generator ∆−b·∇ with “weakly form-bounded” b = b(x), see (23) below, determines for every starting point x ∈ Rd a weak solution to (1) that is, moreover, unique among weak solutions that can be constructed via approximation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' (To the best of the author’s knowledge, this was the first result on weak well-posedness of (1) that included both |b| ∈ Ld(Rd) and the model vector field (4) with δ small;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' it also included the elliptic Morrey class with q > 1 and the Kato class considered by Bass-Chen.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=') Returning to time-inhomogeneous drifts, we note that almost at the same time Wei-Lv-Wu [32], and later Nam [27], obtained results on weak well-posedness of (1) for every x ∈ Rd for time-inhomogeneous vector fields b that can be more singular than the ones in (2).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Nevertheless, their results excluded b = b(x) with |b| ∈ Ld(Rd).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In [21], Krylov proved strong well-posedness of (1), for every initial point and |b| ∈ Ld(Rd), by developing an approach based on his and Veretennikov’s old criterion for a weak solution to be a strong solution [31].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In [33], Xia-Xie-Zhang-Zhao established, among other results, weak well-posedness of (1) for every initial point and b ∈ Cb(R, Ld(Rd)).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Röckner- Zhao [29] furthermore established weak well-posedness of (1), with any x ∈ Rd, for drifts in L∞(R, Ld,w(Rd)), plus the drifts in the critical LPS class.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Here Ld,w(Rd) denotes the weak Ld class that contains vector fields in Ld(Rd), as well as more singular vector fields, such as (4).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In [30], they obtained strong well-posedness of (1), for any starting point and b in the critical LPS class.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In [13], the author and Madou established weak well-posedness of (1), for every starting point and form-bounded drifts, see example 5) below.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' This class contains L∞(R, Ld,w(Rd)) as well as some drifts that are not even in L∞(R, L2+ε(Rd)) for a given ε > 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' By the way, in [18] Semënov, Song and the author showed that the approach of [4] to the strong well-posedness of (1) via the stochastic transport/continuity equations also works for form-bounded vector fields b = b(x), although, again, one obtains strong well-posedness of (1) only for a.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' starting point.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In a recent major advancement, Krylov [23] further verified the Veretennikov-Krylov criterion PARABOLIC EQUATIONS AND SDES WITH TIME-INHOMOGENEOUS MORREY DRIFT 3 for drifts in a large parabolic Morrey class: b ∈ Eq, q > d 2 + 1, (5) see definition below (ignoring here some differences with [23] in the definition of parabolic Morrey class), thus establishing, for every starting point, strong well-posedness of (1) with drift in class (5).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Class (5) contains L∞(R, Ld,w) as well as some drifts that are not in L∞(R, Lq+ε) for a given ε > 0 (see e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' example in [22, Sect.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' 2]).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Let us note in passing that some steps in his proof, such as gradient estimates, are, in fact, carried out for a larger class of form-bounded vector fields.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The above outline does not discuss many interesting results on distribution-valued drifts and on the drifts satisfying additional assumptions on their structure, such as div b ≤ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' We also did not discuss results on partial well-posedness of (1) with |b| ∈ Lp(Rd) in the supercritical regime d 2 < p < d (in the sense of scaling).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In this regard, see Zhao [37].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' In the present paper we consider drifts in the Morrey class Eq with integrability parameter q > 1 that can be chosen arbitrarily close to 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Denote Cr(t, x) := {(s, y) ∈ Rd+1 | t ≤ s ≤ t + r2, |x − y| ≤ r} and, given a vector field b : Rd+1 → Rd with components in Lq loc(Rd+1), q ∈ [1, d + 2], set ∥b∥E+ q := sup r>0,z∈Rd+1 r � 1 |Cr| � Cr(z) |b(t, x)|qdtdx � 1 q and, reversing the direction of time in b, ∥b∥E− q := sup r>0,z∈Rd+1 r � 1 |Cr| � Cr(z) |b(−t, x)|qdtdx � 1 q .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Definition.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' We say that a vector field b belongs to the parabolic Campanato-Morrey (or, for brevity, Morrey) class Eq if ∥b∥Eq := ∥b∥E+ q ∨ ∥b∥E− q < ∞.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' One has ∥b∥Eq ≤ ∥b∥Eq1 if q < q1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' If above b = b(x), then one obtains the usual elliptic Morrey class Mq, that is, |b| ∈ Lq loc(Rd) and ∥b∥Mq := sup r>0,y∈Rd r � 1 |Br| � Br(y) |b(x)|qdx � 1 q < ∞, where Br(y) is the closed ball of radius r centered at y.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Our result, stated briefly, is as follows (see Theorems 1-3 for details).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' We will be using some notations defined in the end of this section.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Theorem.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Let d ≥ 3, let b : Rd+1 → Rd be a vector field in the Morrey class Eq with q > 1 close to 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' Let p ∈]1, ∞[.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' There exists a constant cd,p,q such that if ∥b∥Eq < cd,p,q, then the following are true: 4 D.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' KINZEBULATOV (i) There exists a unique weak solution to (λ − ∂t − ∆ + b(t, x) · ∇)u = 0, t < r, u(r, ·) = g(·) ∈ Lp(Rd) ∩ L2(Rd).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' The difference u(t, ·) − e−λ(r−t) (4π(r − t)) d 2 � Rd e− |·−y|2 4(r−t)g(y)dy (t < r), extended by 0 to t > r, is in the parabolic Bessel potential space W1+ 1 p ,p(Rd+1).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/_NFST4oBgHgl3EQfdDhQ/content/2301.13805v1.pdf'} +page_content=' (ii) For p > d + 1, operators {P t,r}t