Young inequality
= Young inequality
{c}
{wiki=Young's_inequality_for_products}
Young's inequality for products states that for conjugate exponents $q,q'>1$ and nonnegative $a,b$,
$$
ab\leq\frac{a^q}{q}+\frac{b^{q'}}{q'}.
$$
Its weighted form absorbs a lower power into a coercive higher power at the cost of a constant.