112,183 research outputs found
Indasclera hajeki Poloni 2023, n. sp.
No full text<i>Indasclera hajeki</i> n. sp. <p>(Figs. 4–6)</p> <p>Type Material: Holotypus, male, Malaysia, Pahang // Cameron Highlands // Tanah Rata vill. env. // Gonung Jasar [Mt.]; 1470–1705 m // 04°28.4–7’N, 101°21.6–22.1’E // Jiří Hájek leg. 18.iv–10.v.2009 (NMPC).</p>Published as part of <i>Poloni, Riccardo, 2023, Four new species of Indasclera Švihla from the Oriental Region (Coleoptera Oedemeridae), pp. 433-440 in Zootaxa 5336 (3)</i> on page 436, DOI: 10.11646/zootaxa.5336.3.9, <a href="http://zenodo.org/record/8281857">http://zenodo.org/record/8281857</a>
Principal pivot transforms of quasidefinite matrices and semidefinite lagrangian subspaces
No full textLagrangian subspaces are linear subspaces that appear naturally in control theory applications, and especially in the context of algebraic Riccati equations. In this paper, a class of semidefinite Lagrangian subspaces is introduced and it is shown that these subspaces can be represented by a subset I ⊆ 1, 2,..., n and a Hermitian matrix X ∈ Cn×n with the property that the submatrix XII is negative semidefinite and the submatrix XIcIc is positive semidefinite. A matrix X with these definiteness properties is called I-semidefinite and it is a generalization of a quasidefinite matrix. Under mild hypotheses which hold true in most applications, the Lagrangian subspace associated to the stabilizing solution of an algebraic Riccati equation is semidefinite, and in addition it is shown that there is a bijection between Hamiltonian and symplectic pencils and semidefinite Lagrangian subspaces; hence, this structure is ubiquitous in control theory. The (symmetric) principal pivot transform (PPT) is a map used by Mehrmann and Poloni [V. Mehrmann and F. Poloni. Doubling algorithms with permuted Lagrangian graph bases. SIAM J. Matrix Anal. Appl., 33:780–805, 2012. to convert between two different pairs (I,X) and (J,X ′) representing the same Lagrangian subspace. For a semidefinite Lagrangian subspace, it is proven that the symmetric PPT of an I-semidefinite matrix X is a J -semidefinite matrix X ′, and an implementation of the transformation X → X ′ that both makes use of the definiteness properties of X and guarantees the definiteness of the submatrices of X ′ in finite arithmetic is derived. The resulting formulas are used to obtain a semidefiniteness-preserving version of an optimization algorithm introduced by Mehrmann and Poloni to compute a pair (Iopt,Xopt) with Mopt = maxi,j |(Xopt)ij | as small as possible. Using semidefiniteness allows one to obtain a stronger inequality on M with respect to the general case
Alessio Fiore, Alma Poloni, L'economia medievale. Un profilo storico (secoli V-XV)
No full textNegli ultimi vent’anni il panorama degli studi sull’economia medievale ha conosciuto un profondo rinnovamento, anche grazie a inedite tipologie di fonti e a nuove griglie interpretative. Le recenti acquisizioni dell’archeologia hanno contribuito a ridefinire temi quali la produzione e i sistemi di scambio, mentre i dati forniti dai cosiddetti “archivi naturali” hanno permesso di capire meglio questioni cruciali come il rapporto tra ambiente, uomo e risorse. Il dialogo con la scienza economica ha consentito di porre interrogativi diversi alle fonti storiche e di valutare in modo nuovo il ruolo che la domanda, il mercato, i consumi e le istituzioni hanno avuto nel processo di cambiamento economico. È stato inoltre possibile riconsiderare le relazioni di scambio con altre aree di civiltà, collocando l’Europa in un contesto realmente globale. Tenendo conto di queste innovazioni, il libro offre un profilo storico dell’economia medievale che non si presenta come un percorso lineare, ma come un itinerario complesso. Interpretare tale complessità è infatti indispensabile non solo per la comprensione delle società medievali, ma anche per maturare uno sguardo più critico sul nostro presente
Indasclera thailandica Poloni 2023, n. sp.
No full text<i>Indasclera thailandica</i> n. sp. <p>(Fig. 10)</p> <p> <b>Type Material</b>. Holotypus, female: Thailand, Chiang Mai Prov. // Doi Chiang Dao env., 1200 ± 50m, // 19°24’45’’ N 98°51’30’’ E, // L. Dembický leg., 9–13.v.2009 (NMBS). Paratypi: same label, 1♀ (NMBS), 1♀ (RP).</p>Published as part of <i>Poloni, Riccardo, 2023, Four new species of Indasclera Švihla from the Oriental Region (Coleoptera Oedemeridae), pp. 433-440 in Zootaxa 5336 (3)</i> on page 438, DOI: 10.11646/zootaxa.5336.3.9, <a href="http://zenodo.org/record/8281857">http://zenodo.org/record/8281857</a>
Indasclera bipartita Poloni 2023, n. sp.
No full text<i>Indasclera bipartita</i> n. sp. <p>(Figs. 1–3)</p> <p> <b>Type Material</b>. Holotypus, male Laos-NE, Houa Phan prov. // 20°.12–13.5’N 103°59.5’–104°01’E // Ban Saleuy-> Phou Pane Mt. // 1340–1870 m, 1–24.vi.2012, // Vit Kubáň & Lao coll. leg. /// Laos 2012 Expedition, // National Museum Prague, Czech Republic (NMPC). Paratypi: Laos-NE Houa Phan prov., // ~20°13’N 104°00’E, // Phou Pane Mt., // 1–16.vi.2009, 1350–1500, // M. Brancucci leg. /// NHMB Basel, NMPC Prague // Laos 2009 Expedition: // M. Brancucci, M. Geiser, // Z. Kraus, D. Hauck, V. Kubáň, 1♁ (NMPC) 14♁ (NMBS), 8♁ (RP); Laos-NE Houa Phan prov., // ~20°13’N 104°00’E, // Phou Pane Mt., // 9–17.vi.2009, 1300–1900, // Michael Geiser legit /// NHMB Basel, NMPC Prague // Laos 2009 Expedition: // M. Brancucci, M. Geiser, // Z. Kraus, D. Hauck, V. Kubáň, 3♁ (NMBS); Lao-NE, Hua Phan prov. // ~20°12’N 104°01’E, // Phu Phan Mt., 1500- // 1900 m, 17.v.-3.vi.2007, // M. Brancucci leg. /// NHMB Basel, // expedition to // Laos, 2007, 1♁ (NMPC); Laos-NE, Houa Phan prov. // Ban Salouei-> Phou Pane Mt., // 1340–1870 m, 1.v–16.vi.2009, 20°12–13,5’N 103°59,5’–104°0,1’E, // Lao collectors leg.. 17 ♁ (NMPC), 7♁ (RP).</p>Published as part of <i>Poloni, Riccardo, 2023, Four new species of Indasclera Švihla from the Oriental Region (Coleoptera Oedemeridae), pp. 433-440 in Zootaxa 5336 (3)</i> on page 434, DOI: 10.11646/zootaxa.5336.3.9, <a href="http://zenodo.org/record/8281857">http://zenodo.org/record/8281857</a>
Nearest Ω -stable matrix via Riemannian optimization
No full textWe study the problem of finding the nearest Ω-stable matrix to a certain matrix A, i.e., the nearest matrix with all its eigenvalues in a prescribed closed set Ω. Distances are measured in the Frobenius norm. An important special case is finding the nearest Hurwitz or Schur stable matrix, which has applications in systems theory. We describe a reformulation of the task as an optimization problem on the Riemannian manifold of orthogonal (or unitary) matrices. The problem can then be solved using standard methods from the theory of Riemannian optimization. The resulting algorithm is remarkably fast on small-scale and medium-scale matrices, and returns directly a Schur factorization of the minimizer, sidestepping the numerical difficulties associated with eigenvalues with high multiplicity
Johannis Lasitii Nobilis Poloni, De Ecclesiastica Disciplina, Moribusque & Institutis
No full textJOHANNIS LASITII NOBILIS POLONI, DE ECCLESIASTICA DISCIPLINA, MORIBUSQUE & INSTITUTIS
Johannis Lasitii Nobilis Poloni, De Ecclesiastica Disciplina, Moribusque & Institutis ( - )
Cover ( - )
Titelseite mit Apoc. II. v. I. ad. 6. auf Rückseite ( - )
Fraternitatis (3)
Caput I. - X. (13)
Caput XI. - XX. (54)
Caput XXI. - XXX. (99)
Caput XXXI. - XXXIII. (137)
Testimonia quaedam de ordine (151)
Gregorii Franci (171)
Conclusio (174
Duality of matrix pencils and linearizations
No full textIn this paper we introduce a duality relation on matrix pencils and show that it is a useful tool in the theory of linearizations of matrix polynomials. We first completely characterize the Kronecker form of dual pencils. Exploiting this result, we then study the behaviour under duality of the spectral structures, including eigenvalues, eigenvectors, Wong chains, and minimal bases. We also present several applications of the new concept, including: constraints on the minimal indices of singular Hamiltonian and symplectic pencils, new sufficient conditions under which pencils in L1, L2 linearization spaces are strong linearizations, a new perspective on Fiedler pencils, a link between the Möller-Stetter theorem and some linearizations of matrix polynomials
Using permuted graph bases in H-infinity control
No full textWe present a new numerical method (based on the computation of deflating subspaces) for the γ-iteration in H∞ control in the extended matrix pencil formulation. We introduce a permuted graph representation of these subspaces, which avoids the known difficulties that arise when the iteration is based on the solution of algebraic Riccati equations but at the same time makes use of the special symmetry structures that are present in the problems. We use this representation to perform both the deflation of spurious ∞ eigenvalues of the even pencils and the implementation of the inverse-free sign iteration. We show that the new method returns accurate results and is applicable in many situations where conventional methods fail. © 2013 Elsevier Ltd. All rights reserved
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