  The Strong Exponential Time Hypothesis and the OV-conjecture are two popular
hardness assumptions used to prove a plethora of lower bounds, especially in
the realm of polynomial-time algorithms. The OV-conjecture in moderate
dimension states there is no $\epsilon>0$ for which an
$O(N^{2-\epsilon})\mathrm{poly}(D)$ time algorithm can decide whether there is
a pair of orthogonal vectors in a given set of size $N$ that contains
$D$-dimensional binary vectors.
  We strengthen the evidence for these hardness assumptions. In particular, we
show that if the OV-conjecture fails, then two problems for which we are far
from obtaining even tiny improvements over exhaustive search would have
surprisingly fast algorithms. If the OV conjecture is false, then there is a
fixed $\epsilon>0$ such that:
  (1) For all $d$ and all large enough $k$, there is a randomized algorithm
that takes $O(n^{(1-\epsilon)k})$ time to solve the Zero-Weight-$k$-Clique and
Min-Weight-$k$-Clique problems on $d$-hypergraphs with $n$ vertices. As a
consequence, the OV-conjecture is implied by the Weighted Clique conjecture.
  (2) For all $c$, the satisfiability of sparse TC1 circuits on $n$ inputs
(that is, circuits with $cn$ wires, depth $c\log n$, and negation, AND, OR, and
threshold gates) can be computed in time ${O((2-\epsilon)^n)}$.
