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[#P2956] Erdős's sum-distinct set problem for real numbers

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A finite mathematical diagram showing a finite set and its distinct subset sums.
A finite set mapped to its distinct subset sums.

Problem. Erdős Problem 1: A finite set of real numbers $A$ is said to be a sum-distinct set for $N \in \mathbb{N}$ if $A \subseteq (0, N]$ and the subset sums $\sum_{a \in S} a$ differ by at least $1$ for all distinct subsets $S \subseteq A$. That is, for any two distinct subsets $S_1, S_2 \subseteq A$, we have $1 \leq |\sum_{a \in S_1} a - \sum_{a \in S_2} a|$. Determine whether there exists a positive real constant $C$ such that for every nonzero natural number $N$ and every finite set $A \subseteq (0, N]$ that is sum-distinct for $N$, the inequality $C \cdot 2^{|A|} < N$ holds.

1Context

This is a generalization of Erdős's classical problem on sum-distinct sets of integers to the real number setting. The integer version asks whether $N \gg 2^n$ for a sum-distinct set $A \subseteq \{1, \ldots, N\}$ with $|A| = n$, where all subset sums are distinct. The real version relaxes the distinctness condition to require only that subset sums differ by at least $1$.

2Problem setup

Definition 1 (A finite set of real numbers $A$). A finite set of real numbers $A$ is said to be a sum-distinct set for $N \in \mathbb{N}$ if $A \subseteq (0, N]$ and for any two distinct subsets $S_1, S_2 \subseteq A$, the inequality $1 \leq |\sum_{a \in S_1} a - \sum_{a \in S_2} a|$ holds.

Remark 1. This is a generalization of Erdős's classical problem on sum-distinct sets of integers to the real number setting. The integer version asks whether $N \gg 2^n$ for a sum-distinct set $A \subseteq \{1, \ldots, N\}$ with $|A| = n$, where all subset sums are distinct. The real version relaxes the distinctness condition to require only that subset sums differ by at least $1$.

3What counts as a solution

  • Give a rigorous proof or counterexample that completely resolves this statement: Erdős Problem 1: A finite set of real numbers $A$ is said to be a sum-distinct set for $N \in \mathbb{N}$ if $A \subseteq (0, N]$ and the subset sums $\sum_{a \in S} a$ differ by at least $1$ for all distinct subsets $S \subseteq A$. That is, for any two distinct subsets $S_1, S_2 \subseteq A$, we have $1 \leq |\sum_{a \in S_1} a - \sum_{a \in S_2} a|$. Determine whether there exists a positive real constant $C$ such that for every nonzero natural number $N$ and every finite set $A \subseteq (0, N]$ that is sum-distinct for $N$, the inequality $C \cdot 2^{|A|} < N$ holds.

1Status

Current status (Current status and unresolved remainder). OPEN as of 2026-07-31. The maintained Erdős Problems database at commit 8138974387d9030542daabe67faaa33eff9356f8 lists Problem 1 as open. The unresolved remainder is the full displayed statement. Give a rigorous proof or counterexample that completely resolves this statement: Erdős Problem 1: A finite set of real numbers $A$ is said to be a sum-distinct set for $N \in \mathbb{N}$ if $A \subseteq (0, N]$ and the subset sums $\sum_{a \in S} a$ differ by at least $1$ for all distinct subsets $S \subseteq A$. That is, for any two distinct subsets $S_1, S_2 \subseteq A$, we have $1 \leq |\sum_{a \in S_1} a - \sum_{a \in S_2} a|$. Determine whether there exists a positive real constant $C$ such that for every nonzero natural number $N$ and every finite set $A \subseteq (0, N]$ that is sum-distinct for $N$, the inequality $C \cdot 2^{|A|} < N$ holds.[1]

1Packet records

2 records

Notes and companion materialContext, examples, and computations

Original intake status. OPEN as of 2026-07-31. The maintained Erdős Problems database at commit 8138974387d9030542daabe67faaa33eff9356f8 lists Problem 1 as open. The unresolved remainder is the full displayed statement.

  • The maintained database entry for Erdős Problem 1 was open at commit 8138974387d9030542daabe67faaa33eff9356f8.
  • The pinned Formal Conjectures declaration was matched by problem number and source locator.
  • The controlled TheoremDB source corpus was checked for an already published record with the same slug.
How the 2 records connectTyped relations and evidence flow
How the records connect to the problem

ProblemErdős's sum-distinct set problem for real numbers

2See also

How to cite

TheoremDB contributors, “Erdős's sum-distinct set problem for real numbers,” TheoremDB research memory, snapshot of July 31, 2026. https://theoremdb.org/statements/erdos-problem-1

This problem includes 2 records joined by 1 typed links, sourced from erdosproblems.com[1], current as of July 31, 2026.

1References

  1. Packet source. Erdős Problems database, Problem 1, maintained status record. Erdős Problems record 1, checked 2026-08-01. Problem 1; status field and linked bibliography. reference database · reference source · commit 8138974387d9030542daabe67faaa33eff9356f8 · checked 2026-07-31Source use: original summary.Records the current open status and links the literature attached to this exact numbered problem.Also cited at Problem 1; status snapshot 8138974387d9030542daabe67faaa33eff9356f8.Also cited at See dataset.references[0] for the exact external source and locator.Also cited at Editorial research route recorded 2026-07-31.Source used to formulate or check the problem record.Source used to assess the problem's recorded status.For Erdős's sum-distinct set problem for real numbers: Records the current open status and links the literature attached to this exact numbered problem.Source named by the research packet.
  2. Erdős problem database, data/problems.yaml, commit 8138974387d9030542daabe67faaa33eff9356f8. Problem 1 entry in data/problems.yaml. reference database · reference source · commit 8138974387d9030542daabe67faaa33eff9356f8 · checked 2026-07-31Source use: original summary.Pins the maintained database snapshot used for this release's dated status decision.Source used to assess the problem's recorded status.For Erdős's sum-distinct set problem for real numbers: Pins the maintained database snapshot used for this release's dated status decision.
  3. Google DeepMind, Formal Conjectures, formal statement for Erdős Problem 1. GitHub commit bb1c69dab14ad895ac1ccdb7b0c0e0a67c8eb3e1. FormalConjectures/ErdosProblems/1.lean:L115; theorem erdos_1.variants.real; commit bb1c69dab14ad895ac1ccdb7b0c0e0a67c8eb3e1. reference database · primary source · commit bb1c69dab14ad895ac1ccdb7b0c0e0a67c8eb3e1 · checked 2026-07-31Source use: original summary.Supplies the pinned formal declaration whose human-readable editorial statement is published here.Source used to assess the problem's recorded status.For Erdős's sum-distinct set problem for real numbers: Supplies the pinned formal declaration whose human-readable editorial statement is published here.

Original TheoremDB editorial prose based on a pinned formal declaration and the maintained status database.

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