A bijection $\phi:A\to B$ is a <Freiman s-isomorphism> when, for every $a_1,\ldots,a_s,a'_1,\ldots,a'_s\in A$,
$$
a_1+\cdots+a_s=a'_1+\cdots+a'_s
$$
holds if and only if
$$
\phi(a_1)+\cdots+\phi(a_s)
=\phi(a'_1)+\cdots+\phi(a'_s).
$$

Solution

Past exam of the mathematics course of the University of Cambridge / 2021 / iii / Paper 129 / 4 / a / Solution

 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2021/iii/paper-129/4/a/solution