Periodic solutions of perturbed conservative systems
Periodic solutions of perturbed conservative systems
The existence of <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="2 pi"> <mml:semantics> <mml:mrow> <mml:mn>2</mml:mn> <mml:mi>π<!-- π --></mml:mi> </mml:mrow> <mml:annotation encoding="application/x-tex">2\pi</mml:annotation> </mml:semantics> </mml:math> </inline-formula>-periodic solutions to the system <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="x plus grad upper G left-parenthesis x right-parenthesis equals p left-parenthesis t comma x right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mi>x</mml:mi> <mml:mo>+</mml:mo> <mml:mtext>grad</mml:mtext> <mml:mspace …