No CrossRef data available.
Published online by Cambridge University Press: 24 October 2008
Several papers have recently been published which include proofs of the following:
Theorem 1. Those trisecant planes of a rational normal quartic curve Cu which meet a second rational normal quartic curve Cv having six points in common with Cu also meet a third rational normal quartic curve Cw through these same six points. The three suffixes may be permuted in any way, the three curves forming a symmetrical set.
* Welchman, W. G., Proc. Camb. Phil. Soc. 28 (1932), 275CrossRefGoogle Scholar; H. G. Telling, Ibid. 403; D. W. Babbage, Ibid. 421; Semple, J. G., Journal London Math. Soc. 7 (1932), 266.CrossRefGoogle Scholar
† James, C. F. G., Proc. Camb. Phil. Soc. 21 (1923), 673.Google Scholar
* Cf. Edge, , Proc. London Math. Soc. (21), 33 (1931), 53.Google Scholar
* The locus is rational and is represented on [3] by means of cubic surfaces through three skew lines, and in other ways.
* A referee points out that these three systems of [5]'s are dual to the three systems of lines on . In this connection see also James, loc. cit. 674–675. Just as a trisecant plane of determines, by means of the three directrices through its intersections with , a secant [5], so a [4] which meets three generating solids of each in a line contains a directrix of , namely the transversal of the three lines. Viewed from this aspect Theorem 2 is the dual of the statement that any [4] which contains a directrix σ of lying on meets some generating solid of in a line and some generating solid of in a line. The truth of this statement is obvious; both the lines in question are the line σ itself, which is the dual of the space σ6 of Theorem 2.
* This configuration of three lines and three twisted cubics occurs in Welchman's paper: Proc. Camb. Phil. Soc. 28 (1932), 416–420 (418).Google Scholar
* Cf. Telling, loc. cit. 415.
† Segre, , Atti Torino, 19 (1884), 355.Google Scholar
‡ Cf. Baker, , Principles of Geometry, 4 (Cambridge, 1925)Google Scholar, chapter 5; Semple, loc. cit. 270.
* Segre, , Math. Annalen, 27 (1886), 296–314 (302).CrossRefGoogle Scholar