## On a generalization of Markoff’s theory. (Sur une généralisation de la théorie de Markoff.)(French)Zbl 0714.11039

The author generalizes the phenomenon of Markoff forms using the equation $(-\epsilon_ 1A)m^ 2+\epsilon_ 2m^ 2_ 1+\epsilon_ 1m^ 2_ 2=(a+r+1)mm_ 1m_ 2$ for $$\epsilon =\pm 1$$. Using results of R. Remak [Math. Ann. 92, 155–182 (1924; JFM 50.0099.02)] and J. W. S. Cassels [An introduction to diophantine approximation, Cambridge Tract 45 (1957; Zbl 0077.04801)], he constructs trees of forms for which the Markoff spectrum accumulates at $$1/N$$ (for integers $$N>3$$).
Reviewer: Harvey Cohn

### MSC:

 11J06 Markov and Lagrange spectra and generalizations 11D09 Quadratic and bilinear Diophantine equations

### Keywords:

approximation constants; Markoff forms; Markoff spectrum

### Citations:

Zbl 0077.04801; JFM 50.0099.02
Full Text:

### References:

 [1] Markoff, A.A.; Markoff, A.A., Sur LES formes quadratiques binaires indéfinies, Math. ann., Math. ann., 17, 379-399, (1880) · JFM 12.0143.02 [2] Cassels, J.W.S., An introduction to Diophantine approximation, () · Zbl 0077.04801 [3] Remak, R., Uber indefinite binäre quadratische minimal formen, Math. ann., 92, 155-182, (1924) · JFM 50.0099.02 [4] Frobenius, G., Uber die markoffschen zahlen, Preussiche akad. wiss. S.B., 458-487, (1913) · JFM 44.0255.01 [5] Perron, O.; Perron, O., Uber die approximation irrationaler zahlen durch rationale, I, (), Abh. 8 · JFM 48.0193.01 [6] Cusick, T.W.; Flahive, M.E., The markoff and Lagrange spectra, () · Zbl 0685.10023 [7] Perrine, S., Approximation diophantienne, Thèse présentée à l’université de Metz, (Décember 1988), (Théorie de Markoff) [8] Dickson, L.E., ()
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