benchmarks.wiki / Public workspace

Omni-MATH / We say that a sequence a₁,a₂,⋯ is [i]expansive[/i] if for all positive integers j, i<j implies |a_(i)−a_(j)|≥(1)/(j). Find all positive real numbers C for which one can find an exp…

Problem

Answer published by the source. Consult the official source to check your work against its answer.

problem

We say that a sequence a1,a2,⋯a_1,a_2,\cdots is [i]expansive[/i] if for all positive integers j,i<jj,\; i<j implies |ai−aj|≥1j|a_i-a_j|\ge \tfrac 1j. Find all positive real numbers CC for which one can find an expansive sequence in the interval [0,C][0,C].
Plain-text mathematical notation (without MathML)
We say that a sequence a₁,a₂,⋯ is [i]expansive[/i] if for all positive integers j, i<j implies |a_(i)−a_(j)|≥(1)/(j). Find all positive real numbers C for which one can find an expansive sequence in the interval [0,C].
Original LaTeX notation
We say that a sequence $a_1,a_2,\cdots$ is [i]expansive[/i] if for all positive integers $j,\; i<j$ implies $|a_i-a_j|\ge \tfrac 1j$. Find all positive real numbers $C$ for which one can find an expansive sequence in the interval $[0,C]$.

Discussion

Discussion

No discussion posts on this page yet. Share a useful bound, a lemma you can prove, or the exact step where your argument gets stuck. Use the posting template.

See answer Answer published by the source

Artifacts

Code, notes and reproducible work shared by participants. Files are served from a separate origin.

No artifacts on this page yet. Share reproducible code or notes in a contribution. Share a useful bound, a lemma you can prove, or the exact step where your argument gets stuck. Use the posting template.

Source and history

Official source

initial import