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Row of the character table of symmetric group with most negative entries

Posted on 4/22/2022
UQ ID:138
Science
MathOverflow
Original

The row of the character table of corresponding to the trivial representation has all entries positive, and by orthogonality clearly it is the only one like this.

Is it true that for , the row of the character table of corresponding to the sign representation has the most negative entries of any row (about half of them)?

Note that for , in addition to the sign representation row there are two other rows which also have 2 negative entries.

Possibly the fact that row sums are positive is relevant here.

EDIT : see also https://realopacblog.wordpress.com/2025/05/02/maximizing-negative-entries-in-symmetric-group-character-tables/

Keywords & Tags
co.combinatorics
gr.group-theory
rt.representation-theory
symmetric-groups
characters
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K2-Think

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MBZUAI-IFM
Qwen2.5-32B
Sep 18, 2025, 01:50 PM

To address the question of whether the sign representation row in the character table of ( S_n ) has the most negative entries for large ( n ), we analyze the behavior of character values and partition lengths.

Key Observations:

  1. Sign Representation Character Values: The sign representation's character ( \chi^{\text{sign}} ) evaluated at a conjugacy class ( \mu ) (indexed by a p...
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GPT-5

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OpenAI
Sep 2, 2025, 06:56 AM

Short answer: Yes. For large n the sign row is the unique one that maximizes the number of negative entries, and that number is exactly the number of odd conjugacy classes (which is asymptotically half of all conjugacy classes). For small n there are a few ties (e.g. n = 4), but these disappear once n is large enough.

Details and why this is the right order of magnitude:

  • Conjugacy classes in S...
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o4 mini

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OpenAI
Aug 1, 2025, 12:00 AM

Yes. In fact one can show that among all irreducible characters of Sₙ the sign‐character is asymptotically “as negative as possible,’’ and in particular for n≫1 it is the unique row of the character table which comes closest to having half its entries negative. Here is a sketch of the proof.

  1. Notation and the exact count for the sign–row.
    • Let p(n)=# {partitions of n} be the number of...
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o3

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OpenAI
Aug 1, 2025, 12:00 AM

Yes. In fact something much stronger is true:
except for the trivial and for the sign representation every irreducible character of Sₙ is zero on “almost all’’ conjugacy classes, so that the number of negative values it can take is negligible compared with the about one-half attained by the sign character. Consequently the sign character is the (unique) row with the largest number of negativ...

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Claude Opus 4

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Anthropic
Aug 1, 2025, 12:00 AM

This is a very interesting question about the character tables of symmetric groups. Let me analyze what we know and what the question is asking.

The character table of has rows corresponding to irreducible representations (indexed by partitions of ) and columns corresponding to conjugacy classes (also indexed by partitions of ).

Key observations:

  1. The sign representation corre...
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Gemini 2.5 Pro

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Google
Aug 1, 2025, 12:00 AM

An excellent and subtle question. The user's hypothesis is that for large , the sign character has the most negative entries in the character table of . Let's analyze this claim.

Summary of the Conclusion

The user's conjecture is plausible and points in the right direction, but is unlikely to be true in its strongest form (that the sign representation is the unique m...

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DeepSeek R1

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DeepSeek
deepseek-ai/DeepSeek-R1
Aug 1, 2025, 12:00 AM
<think> I need to answer this question about the character table of the symmetric group \( S_n \). The question asks whether, for large \( n \), the row corresponding to the sign representation has the most negative entries, and specifically, about half of them.

First, recall that the character table of ( S_n ) is based on its irreducible representations, which are indexed by partitions of ( n...

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Claude 3.7 Sonnet

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Anthropic
Aug 1, 2025, 12:00 AM

Row of the Character Table of Symmetric Group with Most Negative Entries

This question is about determining which row of the character table of the symmetric group has the most negative entries, particularly for large .

Analysis of the Sign Representation

The sign representation of corresponds to the partition . For a permutation with cycle structure corresponding to ...

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o3 Pro

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OpenAI
Aug 1, 2025, 12:00 AM

At the moment nobody knows a proof (or a counter–example) of the statement

“For all sufficiently large n the sign character has strictly more
negative values than every other irreducible character of S n”.

What is known is the following.

  1. Computations.
    • With GAP/MAGMA one can list every irreducible character of S n and count on how many conjugacy classes it is negative.
    ...
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