  Assuming the Exponential Time Hypothesis (ETH), a result of Marx (ToC'10)
implies that there is no $f(k)\cdot n^{o(k/\log k)}$ time algorithm that can
solve 2-CSPs with $k$ constraints (over a domain of arbitrary large size $n$)
for any computable function $f$. This lower bound is widely used to show that
certain parameterized problems cannot be solved in time $f(k)\cdot n^{o(k/\log
k)}$ time (assuming the ETH). The purpose of this note is to give a streamlined
proof of this result.
