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pro vyhledávání: '"P Uldall"'
In this paper, we study normal forms of analytic saddle-nodes in $\mathbb C^n$ with any Poincar\'e rank $k\in \mathbb N$. The approach and the results generalize those of Bonchaert and De Maesschalck from 2008 that considered $k=1$. In particular, we
Externí odkaz:
http://arxiv.org/abs/2410.20854
Autor:
Kristiansen, Kristian Uldall
In this paper, we show that the coefficients $\phi_n$ of the formal series expansions $y=\sum_{n=1}^\infty \phi_n x^n\in x\mathbb C[[x]]$ of center manifolds of planar analytic saddle-nodes grow like $\Gamma(n+a)$ (after rescaling $x$) as $n\rightarr
Externí odkaz:
http://arxiv.org/abs/2410.08088
We prove the existence of a family of travelling wave solutions in a variant of the $\textit{Zeldovich-Frank-Kamenetskii (ZFK) equation}$, a reaction-diffusion equation which models the propagation of planar laminar premixed flames in combustion theo
Externí odkaz:
http://arxiv.org/abs/2405.10076
Any attracting, hyperbolic and proper node of a two-dimensional analytic vector-field has a unique strong-stable manifold. This manifold is analytic. The corresponding weak-stable manifolds are, on the other hand, not unique, but in the nonresonant c
Externí odkaz:
http://arxiv.org/abs/2403.01488
In this paper, we revisit the damped Kepler problem within a general family of nonlinear damping forces with magnitude $\delta \vert u\vert^{\beta}\vert \dot u\vert^{\alpha+1}$, depending on three parameters $\delta>0,\alpha\ge 0$ and $\beta\ge 0$, a
Externí odkaz:
http://arxiv.org/abs/2312.07249
The goal of this paper is to study the number of sliding limit cycles of a regularized piecewise linear $VI_3$ two-fold using the notion of slow divergence integral. We focus on limit cycles produced by canard cycles located in the half-plane with an
Externí odkaz:
http://arxiv.org/abs/2310.07230
In this paper we define the notion of slow divergence integral along sliding segments in regularized planar piecewise smooth systems. The boundary of such segments may contain diverse tangency points. We show that the slow divergence integral is inva
Externí odkaz:
http://arxiv.org/abs/2310.06719
Autor:
Kristiansen, Kristian Uldall
In this paper, we revisit the Kepler problem with linear drag. With dissipation, the energy and the angular momentum are both decreasing, but in \cite{margheri2017a} it was shown that the eccentricity vector has a well-defined limit in the case of li
Externí odkaz:
http://arxiv.org/abs/2303.00283
Publikováno v:
Revista Venezolana de Gerencia, Vol 29, Iss 108 (2024)
The national R&D system is a concept that has gained significant recognition; however, measuring it is challenging and not devoid of difficulties. In this paper the method of composite variables is applied to configure R&D systems and with this exami
Externí odkaz:
https://doaj.org/article/1a706562a8af40a2a03e75b5953cc79f
Publikováno v:
Scientific Reports, Vol 14, Iss 1, Pp 1-9 (2024)
Abstract Different diagnoses of thyroid disease are available in the 10th International Classification of Diseases (ICD-10), but the validity of diagnoses related to obstetric and postpartum thyroid disease is unknown. This was a retrospective cohort
Externí odkaz:
https://doaj.org/article/56462258ad934a47bc0ad89dc39264e6