Felix Klein's paper on real flexes vindicated

Felice Ronga

Banach Center Publications (1998)

  • Volume: 44, Issue: 1, page 195-210
  • ISSN: 0137-6934

Abstract

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In a paper written in 1876 [4], Felix Klein gave a formula relating the number of real flexes of a generic real plane projective curve to the number of real bitangents at non-real points and the degree, which shows in particular that the number of real flexes cannot exceed one third of the total number of flexes. We show that Klein's arguments can be made rigorous using a little of the theory of singularities of maps, justifying in particular his resort to explicit examples.

How to cite

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Ronga, Felice. "Felix Klein's paper on real flexes vindicated." Banach Center Publications 44.1 (1998): 195-210. <http://eudml.org/doc/208883>.

@article{Ronga1998,
abstract = {In a paper written in 1876 [4], Felix Klein gave a formula relating the number of real flexes of a generic real plane projective curve to the number of real bitangents at non-real points and the degree, which shows in particular that the number of real flexes cannot exceed one third of the total number of flexes. We show that Klein's arguments can be made rigorous using a little of the theory of singularities of maps, justifying in particular his resort to explicit examples.},
author = {Ronga, Felice},
journal = {Banach Center Publications},
keywords = {enumerative problems; JFM 08.0439.01; number of real flexes; real plane projective curve},
language = {eng},
number = {1},
pages = {195-210},
title = {Felix Klein's paper on real flexes vindicated},
url = {http://eudml.org/doc/208883},
volume = {44},
year = {1998},
}

TY - JOUR
AU - Ronga, Felice
TI - Felix Klein's paper on real flexes vindicated
JO - Banach Center Publications
PY - 1998
VL - 44
IS - 1
SP - 195
EP - 210
AB - In a paper written in 1876 [4], Felix Klein gave a formula relating the number of real flexes of a generic real plane projective curve to the number of real bitangents at non-real points and the degree, which shows in particular that the number of real flexes cannot exceed one third of the total number of flexes. We show that Klein's arguments can be made rigorous using a little of the theory of singularities of maps, justifying in particular his resort to explicit examples.
LA - eng
KW - enumerative problems; JFM 08.0439.01; number of real flexes; real plane projective curve
UR - http://eudml.org/doc/208883
ER -

References

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  1. [1] S. Akbulut (ed.), Real Algebraic Geometry and Topology, Contemp. Math. 182, Amer. Math. Soc., Providence, 1996. 
  2. [2] R. Benedetti and R. Silhol, Spin and P i n - structures, immersed and embedded surfaces and a result of B. Segre on real cubic surfaces, Topology 34 (1995), 651-678. Zbl0996.57519
  3. [3] M. Golubitsky and V. Guillemin, Stable Mappings and their Singularities, Springer, New York-Heidelberg 1973. Zbl0294.58004
  4. [4] F. Klein, Eine neue Relation zwischen den Singularitäten einer algebraischen Curve, Math. Ann. 10 (1876), 199-209. 
  5. [5] I. R. Porteous, Simple Singularities of Maps, preprint, Columbia Univ., 1962, reprinted in: Proc. of the Liverpool Singularities Symp., Lecture Notes in Math. 192, Springer, Berlin, 1971, 217-236. 
  6. [6] F. Sottile, Enumerative Geometry for real Varieties, to appear. 
  7. [7] R. Thom, Stabilité structurelle et morphogénèse, W. A. Benjamin, Reading, 1972. 
  8. [8] O. Ya. Viro, Some integral calculus based on Euler characteristic, in: Topology and Geometry - Rohlin Seminar, Lecture Notes in Math. 1346, Springer, Berlin, 1988. 
  9. [9] C. T. C. Wall, Duality of real projective plane curves: Klein's equation, Topology 35 (1996), 355-362. Zbl0894.14013
  10. [10] H. G. Zeuthen, Sur les différentes formes des courbes planes du quatrième ordre, Math. Ann. 7 (1874), 410-432. 

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