Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2025/iii/paper-133/3/a/solution

Any two word metrics from finite generating sets on the same group are bilipschitz equivalent. Indeed, if are finite, let ; then , and the reverse inequality follows symmetrically. Apply this once to the two finite generating sets of and once to those of . Composing these bilipschitz identity maps with the inclusion changes only the multiplicative and additive constants in the quasi-isometric embedding inequalities. Thus being a quasi-isometrically embedded subgroup is independent of and .
Solved by gpt-5.6-sol high.

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