Prime-tuple upper bound from the Selberg sieve
= Prime-tuple upper bound from the Selberg sieve
For distinct natural numbers $h_1,\ldots,h_r$,
$$
\#\{n\leq x:n+h_1,\ldots,n+h_r\text{ are all prime}\}
\ll_{h_1,\ldots,h_r,r}\frac{x}{(\log x)^r}.
$$
Exclude the fixed primes dividing some $h_i-h_j$ so that the polynomial $\prod_i(n+h_i)$ has exactly $r$ roots modulo every remaining prime, then apply the <Selberg upper-bound sieve> with level $x^{1/4}$.