252 research outputs found
Poincaré and Analysis Situs, the beginning of algebraic topology
No full textIn 1895 Henri Poincaré published his topological work ‘Analysis Situs’. A new subdiscipline inmathematics was born. Analysis Situs was an inspiration to new fields like algebraic topology,Morse theory and cobordism. With use of today’s knowledge and notation, Dirk Siersma viewsback to this historical work of Poincaré
Visie op wiskundeonderwijs
No full textIn zijn afscheidscollege, gehouden op 10 september 2008 aan de Universiteit Utrecht, vertelde Dirk Siersma onder andere over zijn werk binnen de commissie Toekomst Wiskunde Onderwijs. Deze commissie houdt zich bezig met het samenstellen van een nieuw eindexamenprogramma wiskunde voor havo en vwo. Uit onderstaande tekst, afkomstig uit deze rede, blijkt dat hij zich zorgen maakt over de polarisatie in de onderwijsdiscussie
Poincaré and Analysis Situs, the beginning of algebraic topology
No full textIn 1895 Henri Poincaré published his topological work ‘Analysis Situs’. A new subdiscipline inmathematics was born. Analysis Situs was an inspiration to new fields like algebraic topology,Morse theory and cobordism. With use of today’s knowledge and notation, Dirk Siersma viewsback to this historical work of Poincaré
Curvatures of conflict surfaces in Euclidean 3-space
No full textThis article extends to three dimensions results on the curvature of the conflict curve for pairs of convex sets of the plane established by Siersma In the present case a conflict surface arises equidistant from the given convex sets The Gaussian Mean Curvatures and the location of Umbilic Points on the conflict surface are determined here Initial results on the Darbouxian type of Umbilic Points on conict surfaces are also established The results are expressed in terms of the principal directions and on the curvatures of the borders of the given convex set
sj-pdf-1-ajs-10.1177_03635465221110214 – Supplemental material for Effects of Heavy Slow Resistance Training Combined With Corticosteroid Injections or Tendon Needling in Patients With Lateral Elbow Tendinopathy: A 3-Arm Randomized Double-Blinded Placebo-Controlled Study
No full textSupplemental material, sj-pdf-1-ajs-10.1177_03635465221110214 for Effects of Heavy Slow Resistance Training Combined With Corticosteroid Injections or Tendon Needling in Patients With Lateral Elbow Tendinopathy: A 3-Arm Randomized Double-Blinded Placebo-Controlled Study by Christian Couppé, Simon Døssing, Per Martin Bülow, Volkert Dirk Siersma, Camilla Kampp Zilmer, Christine Winther Bang, Rikke Høffner, Mathilde Kracht, Paul Hogg, Gabriella Edström, Michael Kjaer and Stig Peter Magnusson in The American Journal of Sports Medicine</p
Curvatures of Conflict Surfaces in Euclidean 3-Space
No full textThis article extends to three dimensions results on the curvature of the conflict curve for pairs of convex sets of the plane, established by Siersma [3]. In the present case a conflict surface arises, equidistant from the given convex sets. The Gaussian, mean curvatures and the location of umbilic points on the conflict surface are determined here. Initial results on the Darbouxian type of umbilic points on conflict surfaces are also established. The results are expressed in terms of the principal directions and on the curvatures of the borders of the given convex sets
Betti bounds of polynomials
No full textWe initiate a classification of polynomials f : Cn - C of degree d having the top Betti number of the general fibre close to the maximum. We find a range in which the polynomial must have isolated singularities and another range where it may have at most one line singularity of Morse transversal type. Our method uses deformations into particular pencils with non-isolated singularitie
Characterizations of Simple Isolated Line Singularities
No full textAbstractA line singularity is a function germ with a smooth 1-dimensional critical set . An isolated line singularity is defined by the condition that for every x ≠ 0, the germ of f at (x, 0) is equivalent to . Simple isolated line singularities were classified by Dirk Siersma and are analogous of the famous A − D − E singularities. We give two new characterizations of simple isolated line singularities.</jats:p
Non reduced plane curve singularities with b1(F)=0 and Bobadilla's question
No full textIf the first Betti number of the Milnor fibre of a plane curve singularity is zero, then the defining function is equivalent to xr
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