Duality of Measure and Category in Infinite-Dimensional Separable Hilbert Space<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="$\ell_2$" id="E1"><mml:mrow><mml:msub><mml:mi>ℓ</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
International journal of mathematics and mathematical sciences