Elliptic and parabolic BMO and Harnack’s inequality
Elliptic and parabolic BMO and Harnack’s inequality
We give a generalization of the John-Nirenberg lemma which can be applied to prove <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper A 2"> <mml:semantics> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi>A</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> <mml:annotation encoding="application/x-tex">{A_2}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> type conditions for small powers of positive solutions of elliptic and parabolic, degenerate and nondegenerate operators.