= Unit sphere net from ball covering
{title2=$|\mathcal N_\delta|\leq(2A/\delta)^k$}
A cover of the <unit ball> by balls of radius $\delta/2$ gives a radius-$\delta$ <metric net> on the <unit sphere>: discard balls missing the sphere and choose a sphere point in each remaining ball. Every sphere point lies within $\delta$ of the selected point in its ball. The argument keeps the number of balls and ensures that the selected points have unit length, regardless of the initial covering centers.
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