Abstract
Here it is proved that if Q(x 1,..., x n) is a positive definite quadratic form which is reduced in the sense of Korkine and Zolotareff and has outer coefficients B 1,..., B n satisfying B 1 ≥ 1) B n ≤ 1 and B 1 ⋯ B n = 1, then its inhomogeneous minimum is at most n/4 for n ≤ 7. This result implies a positive answer to a question of Shapira and Weiss for stable lattices and thereby provides another proof of Minkowski’s Conjecture on the product of n real non-homogeneous linear forms in n variables for n ≤ 7. Our result is an analogue of Woods’ Conjecture which has been proved for n ≤ 9. The analogous problem when B 11 is also investigated.
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References
B.J. Birch and H.P.F. Swinnerton-Dyer, On the inhomogeneous minimum of the product of n linear forms, Mathematika 3 (1956), 25–39.
H.F. Blichfeldt, The minimum values of positive quadratic forms in six, seven and eight variables, Math. Z., 39 (1934), 1–15.
M. Dutour-Sikiric, Enumeration of inhomogeneous perfect forms, 2013. Manuscript in preparation.
M. Dutour-Sikiric, A. Schurmann, and F. Vallentin, Inhomogeneous extreme forms, Ann. Inst. Fourier (Grenoble), 62(6) (2012), 2227–2255.
P. Gruber, Convex and discrete geometry, Springer Grundlehren Series, Vol.336 (2007).
R.J. Hans-Gill, Madhu Raka and Ranjeet Sehmi, On conjectures of Minkowski and Woods for n = 7, J. Number Theory, 129 (2009), 1011–1033.
R.J. Hans-Gill, Madhu Raka and Ranjeet Sehmi, On Conjectures of Minkowski and Woods for n = 8, Acta Arithmetica, 147(4) (2011), 337–385.
Leetika Kathuria and Madhu Raka, On Conjectures of Minkowski and Woods for n = 9, arXiv: 1410.5743vl [math.NT], 21 Oct, 2014.
A. Korkine and G. Zolotareff, Sur les formes quadratiques, Math. Ann., 6 (1873), 366-389; Sur les formes quadratiques positives, Math. Ann., 11 (1877), 242-292.
C.T. McMullen, Minkowski’s conjecture, well rounded lattices and topological dimension, J. Amer. Math. Soc., 18 (2005), 711–734.
Uri Shapira and Barak Weiss, On the stable lattices and the diagonal group, arXiv: 1309.4025vl [math.DS] 16 September 2013.
A.C. Woods, The densest double lattice packing of four spheres, Mathematika, 12 (1965), 138–142.
A.C. Woods, Lattice coverings of five space by spheres, Mathematika, 12 (1965), 143–150.
A.C. Woods, Covering six space with spheres, J. Number Theory, 4 (1972), 157–180.
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The author acknowledges the support of CSIR, India
The author acknowledges the support of Indian National Science Academy during the period when the results of this paper were obtained
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Kathuria, L., Hans-Gill, R.J. & Raka, M. On a question of Uri Shapira and Barak Weiss. Indian J Pure Appl Math 46, 287–307 (2015). https://doi.org/10.1007/s13226-015-0123-x
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DOI: https://doi.org/10.1007/s13226-015-0123-x