Note Sur LeBetula Pubescens

Une note sur les contractions dans les polygones orthogonaux

Maire, F., Une note sur les contractions dans les polygones orthogonaux, Discrete Mathematics 111 (1993) 3677371. We define a contraction for orthogonal polygons, and show that such a polygon can be transformed into a rectangle by a sequence of contractions. This result gives a new proof of the orthogonal art gallery theorem. We present also a property of the maximal rectangles contained in ort...

Note sur la sémantique des structures de contrôle

Note sur la Suppression des Étiquettes en Programmation

A Note on Signs of Kloosterman Sums (une Note Sur Les Signes Des Sommes De Kloosterman)

We prove that the sign of Kloosterman sums Kl(1, 1;n) changes infinitely often as n runs through the square-free numbers with at most 15 prime factors. This improves on a previous result by Sivak-Fischler who obtained 18 instead of 15. Our improvement comes from introducing an elementary inequality which gives lower and upper bounds for the dot product of two sequences whose individual distribu...

Flavonol glycosides from Epimedium pubescens.

Five new flavonol glycosides (1, 3, 5-7) were isolated from the aerial parts of Epimedium pubescens Maxim., along with two known compounds, sagittasine C (2) and 4',5-dihydroxyl-8-(3,3-dimethylallyl)-flavonol 3-O-[β-D-xylopyranosyl(1→3)-4-O-acetyl-α-L-rhamnopyranoside]-7-O-β-D-glucopyranoside (4). The structures were elucidated on the basis of their 1D-, 2D-NMR, MS, UV and IR spectra data.