On invariant sets and on a theorem of Ważewski
On invariant sets and on a theorem of Ważewski
The first part of the paper treats the question of the existence of a solution <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="x equals x left-parenthesis t right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mi>x</mml:mi> <mml:mo>=</mml:mo> <mml:mi>x</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">x = x(t)</mml:annotation> </mml:semantics> </mml:math> </inline-formula> of an ordinary differential equation which exists …