On the product of three homogeneous linear forms and indefinite ternary quadratic forms

1955 ◽  
Vol 248 (940) ◽  
pp. 73-96 ◽  
Keyword(s):  
Lower Bound ◽  
Quadratic Forms ◽  
Type A ◽  
Strong Type ◽  
Geometry Of Numbers ◽  
Linear Forms ◽  
Integer Coefficients ◽  
Ternary Quadratic Forms ◽  
Cubic Forms ◽  
Homogeneous Linear

Isolation theorems for the minima of factorizable homogeneous ternary cubic forms and of indefinite ternary quadratic forms of a new strong type are proved. The problems whether there exist such forms with positive minima other than multiples of forms with integer coefficients are shown to be equivalent to problems in the geometry of numbers of a superficially different type. A contribution is made to the study of the problem whether there exist real <j>, ijr such that x(f>x—y | y[rx — z | has a positive lower bound for all integers x > 0, y , z . The methods used have wide validity.

On the Product of Three Homogeneous Linear Forms. IV

1943 ◽  
Vol 39 (1) ◽  
pp. 1-21 ◽  
Author(s):  
H. Davenport
Keyword(s):  
Lower Bound ◽  
Real Number ◽  
Linear Transformation ◽  
Linear Forms ◽  
Special Linear ◽  
Absolute Value ◽  
Cubic Equation ◽  
Image Position ◽  
Homogeneous Linear

Let L1, L2, L3 be three homogeneous linear forms in u, v, w with real coefficients and determinant 1. Let M denote the lower bound offor integral values of u, v, w, not all zero. I proved a few years ago (1) thatmore precisely, thatexcept when L1, L2, L3 are of a special type, in which case If we denote by θ, ø, ψ the roots of the cubic equation t3+t2-2t-1 = 0, the special linear forms are equivalent, by an integral unimodular linear transformation, to(in any order), where λ1,λ2,λ3 are real number whose product is In this case, L1L2L3|λ1λ2λ3 is a non-zero integer, and the minimum of its absolute value is 1, giving

Asymmetric inequalities for non-homogeneous ternary quadratic forms

1967 ◽  
Vol 63 (2) ◽  
pp. 291-303 ◽  
Author(s):  
Vishwa Chander Dumir
Keyword(s):  
Quadratic Forms ◽  
Real Numbers ◽  
Linear Forms ◽  
Ternary Quadratic Forms ◽  
Image Position

A well-known theorem of Minkowski on the product of two linear forms states that ifare two linear forms with real coefficients and determinant Δ = |αδ − βγ| ≠ 0, then given any real numbers c1, c2 we can find integers x, y such that

Groups of units of zero ternary quadratic forms

1981 ◽  
Vol 88 (1-2) ◽  
pp. 141-157 ◽  
Author(s):  
Colin Maclachlan
Keyword(s):  
Finite Index ◽  
Quadratic Forms ◽  
Modular Group ◽  
Conjugacy Classes ◽  
Rational Integer ◽  
Fuchsian Groups ◽  
Integer Coefficients ◽  
Ternary Quadratic Forms

SynopsisThe groups of units of indefinite ternary quadratic forms with rational integer coefficients contain subgroups of index two which are isomorphic to Fuchsian groups and which, for zero forms, are commensurable with the classical modular group. This is used to obtain a family of forms whose groups are representatives of the conjugacy classes of maximal groups associated with zero forms. The signatures of the groups of the forms in this family are determined and it is shown that the group associated to any zero form is isomorphic to a subgroup of finite index in the group of one of three particular forms. This last result should be compared with the corresponding result by Mennicke on non-zero forms.

Complex homogeneous linear forms

1956 ◽  
Vol 52 (1) ◽  
pp. 35-38 ◽  
Author(s):  
K. Rogers
Keyword(s):  
Complex Space ◽  
Rational Numbers ◽  
Quadratic Equation ◽  
Complex Numbers ◽  
Geometry Of Numbers ◽  
Systematic Method ◽  
Linear Forms ◽  
Rings Of Integers ◽  
Image Position ◽  
Homogeneous Linear

Let Z, Q, C denote respectively the ring of rational integers, the field of rational numbers and the field of complex numbers. Minkowski (4) solved the problem of minimizingfor x, y ∈ Z(i) or Z(ρ), where a, b, c, d ∈ C have fixed determinant Δ ≠ 0. Here ρ = exp 2/3πi, and Z(i) and Z(p) are the rings of integers in Q(i) and Q(ρ) respectively. In fact he found the best possible resultsfor Z(i), andfor Z(ρ), wherewhile Buchner (1) used Minkowski's method to show thatfor Z(i√2). Hlawka(3) has also proved (1·2), and Cassels, Ledermann and Mahler (2) have proved both (1·2) and (1·3). In a paper being prepared jointly by H. P. F. Swinnerton-Dyer and the author, general problems of the geometry of numbers in complex space are discussed and a systematic method given for solving the above problem for all complex quadratic fields Q(ϑ). Here, ϑ is a non-real number satisfying. an irreduc7ible quadratic equation with rational coefficients. The above problem is solved in detail for Q(i√5), for whichand the ‘critical forms’ can be reduced to

XXV.—On the Groups of Units of Ternary Quadratic Forms with Rational Coefficients

1967 ◽  
Vol 67 (4) ◽  
pp. 309-352 ◽  
Author(s):  
J. Mennicke
Keyword(s):  
Finite Number ◽  
Quadratic Forms ◽  
Rational Integer ◽  
Fuchsian Groups ◽  
Finitely Generated ◽  
Integer Coefficients ◽  
Ternary Quadratic Forms ◽  
Complete Survey

SynopsisFuchsian groups that are unit groups of ternary quadratic forms with rational integer coefficients are studied. By means of the well-known Nielsen classification of finitely generated Fuchsian groups, a complete survey of the unit groups is given. For this, we have to use the arithmetical methods of B. W. Jones. In the second part, the relations between Fuchsian groups arising from different quadratic forms are studied. It turns out that, with a finite number of exceptions, all these Fuchsian groups are subgroups of a particular one.

FINITENESS RESULTS FOR REGULAR DEFINITE TERNARY QUADRATIC FORMS OVER ${\mathbb Q}(\sqrt{5})$

2007 ◽  
Vol 03 (04) ◽  
pp. 541-556 ◽  
Author(s):  
WAI KIU CHAN ◽  
A. G. EARNEST ◽  
MARIA INES ICAZA ◽  
JI YOUNG KIM
Keyword(s):  
Quadratic Form ◽  
Number Field ◽  
Quadratic Forms ◽  
Positive Definite ◽  
Integral Quadratic Form ◽  
Ring Of Integers ◽  
Ternary Quadratic Forms ◽  
Totally Positive ◽  
Finiteness Result

Let 𝔬 be the ring of integers in a number field. An integral quadratic form over 𝔬 is called regular if it represents all integers in 𝔬 that are represented by its genus. In [13,14] Watson proved that there are only finitely many inequivalent positive definite primitive integral regular ternary quadratic forms over ℤ. In this paper, we generalize Watson's result to totally positive regular ternary quadratic forms over [Formula: see text]. We also show that the same finiteness result holds for totally positive definite spinor regular ternary quadratic forms over [Formula: see text], and thus extends the corresponding finiteness results for spinor regular quadratic forms over ℤ obtained in [1,3].

Isolated minima of the product of n linear forms

1953 ◽  
Vol 49 (1) ◽  
pp. 59-62 ◽  
Author(s):  
E. S. Barnes
Keyword(s):  
Lower Bound ◽  
Upper Bound ◽  
Linear Forms ◽  
Image Position

Letbe n linear forms with real coefficients and determinant Δ = ∥ aij∥ ≠ 0; and denote by M(X) the lower bound of | X1X2 … Xn| over all integer sets (u) ≠ (0). It is well known that γn, the upper bound of M(X)/|Δ| over all sets of forms Xi, is finite, and the value of γn has been determined when n = 2 and n = 3.

Sign in / Sign up

Export Citation Format

Share Document