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Elementary proofs of Peano's existence theorem

Published online by Cambridge University Press:  09 April 2009

M. A. Dow
Affiliation:
Department of Mathematics University of Queensland, Australia.
R. Výborný
Affiliation:
Department of Mathematics University of Queensland, Australia.
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An “elementary” proof of Peano's existence theorem is given that, in addition to avoiding the Ascoli lemma, relies neither on Dini's theorem, nor on uniform continuity of the right hand side of φ' = f(t,φ). It is based on superfunctions. Also, another standard proof of that theorem, based on approximation of the right hand side, is made elementary.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1973

References

[1]Kennedy, H. C., ‘Is there an elementary proof of Peano's existence theorem for first order differential equations?Amer. Math. Monthly, 76 (1969), 10431045.Google Scholar
[2]Peano, G., Opere Scelte, vol. 1 (Edizioni Cremonese, 1957).Google Scholar
[3]Perron, O., ‘Ein neuer Existenzbeweis für die Integrale der Differentialgleichung y' = f(x, y)’, Math. Ann. 76 (1915), 471484.Google Scholar
[4]Walter, W., ‘There is an elementary proof of Peano's existence theorem’, Amer. Math. Monthly, 78 (1971), 170173.Google Scholar
[5]Grunsky, H., ‘Ein konstrucktiver Beweis für die Lösbarkeit der Differentialgleichung y' = f(x, y) bei stetigem f(x, y)’, Jahresber. Deutsch. Math. Ver., Abt. 1, 63 (1960), 7884.Google Scholar
[6]Walter, W., Differential and Integral Inequalities (Springer Verlag, 1970).CrossRefGoogle Scholar
[7]Aziz, A. K. and Diaz, J. B., ‘On Pompeiu's proof of the mean-value theorem of the differential calculus of real-valued functions’, Contributions to Differential Equations, 1 (1963), 467481.Google Scholar
[8]Diaz, J. B. and Výborný, R., ‘On mean value theorems for strongly continuous vector valued functions’, Contributions to Differential Equations, 3 (1964), 107118.Google Scholar