Existence of positive solutions for some polyharmonic nonlinear equations in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="$\mathbb{R}^{n}$" id="E1"><mml:mrow><mml:msup><mml:mi>ℝ</mml:mi><mml:mi>n</mml:mi></mml:msup></mml:mrow></mml:math>
Abstract and applied analysis