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A long-standing conjecture of Erdős and Simonovits asserts that for every rational number
$r\in (1,2)$
there exists a bipartite graph H such that
$\mathrm{ex}(n,H)=\Theta(n^r)$
. So far this conjecture is known to be true only for rationals of form
$1+1/k$
and
$2-1/k$
, for integers
$k\geq 2$
. In this paper, we add a new form of rationals for which the conjecture is true:
$2-2/(2k+1)$
, for
$k\geq 2$
. This in turn also gives an affirmative answer to a question of Pinchasi and Sharir on cube-like graphs. Recently, a version of Erdős and Simonovits
$^{\prime}$
s conjecture, where one replaces a single graph by a finite family, was confirmed by Bukh and Conlon. They proposed a construction of bipartite graphs which should satisfy Erdős and Simonovits
$^{\prime}$
s conjecture. Our result can also be viewed as a first step towards verifying Bukh and Conlon
$^{\prime}$
s conjecture. We also prove an upper bound on the Turán number of theta graphs in an asymmetric setting and employ this result to obtain another new rational exponent for Turán exponents:
$r=7/5$
.
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