Vol. 6 No. 3 (1972)

Ringkasan. Suatu matriks kwadratis kita katakana fundamental djika ia simetris dan setiap submatriks utamanja mempunjai deretminan jang positif. Misalkan f suatu bentuk bilinier pada suatu ruang vector berdimensi hingga atas lapangan riil, dan f berkoresponensi dengan suatu matriks G. kita buktikan, bahwa f suatu hasilkali-dalam djika dan hanja djika G fundamental.Abstract. We define a square matrix to be fundamental if it is symmetric and all its principal submatrices have positive determinants. Let f be a bilinear form on finite-dimensional vector space over the real field which corresponds…

. A study has been made of the species of Cyanophyceae occurring in the rhizosphere and nonrhizosphere regions of soybeans in pot culture under glasshouse conditions. Eleven species of Cyanophyceae were detected. The algal species were not influenced in diversity by the presence of Rh. japonicum. Very few cells of only four species occurred in unplanted pots. Attention is drawn to the dearth of information available on rhizosphere algae and to their likely importance for the heterotrophic populations. Ringkasan. Penelitian terhadap species Cyanophyceae jang terdapat didaerah rhizosphere dan…

. Several pyroclastic plateaux are known in the Padang Highlands. Westerveld (1952) suggested that those rhyolitic volcanics are sheetlike deposits of paroxysmal fissure eruption similar to the incandescent clouds of the Katmai type. Field observation, however, suggested that at least the pyroclastic plateau of Bukit Tinggi might as well be the result of an air borne tuff deposition which originated from a gigantic outburst of the Manindjau volcano prior to its caldera formation. The tuff plateau of Bukit Tinggi, as revealed by the exposures in Ngarai SiAnok, is neither layered nor welded and…

. Magnitudes and colors in the UBV photometric system have been determined for 575 stars in and around NGC 6866. The color-color relation of the cluster stars provides an estimate of interstellar reddening of 0.16 mag. The distance of cluster is found to be 1336 pc. The age, as determined from the evolutionary deviation curve, is approximately 2.5 x 108 years. Ringkasan. Magnitudo dan warna dalam sistim UBV-photometri untuk 575 buah bintang disekitar NGC 6866 telah diukur setjara photographi-photometri. Excess warna, jang diturunkan dari diagram warna-warna, telah ditentukan sebesar 0.16…