The uniqueness conjecture for subunit index-ratio classes

Let GkG_k denote the set of positive integers whose index ratio is kk. Uniqueness conjecture for subunit index-ratio classes. If k<1k<1, then GkG_k is either empty or has only one element. The preceding discussion rules out prime powers from GkG_k when kk is a unit fraction, but no general proof of the asserted uniqueness or emptiness is given; the conjecture is motivated by numerical computations and remains open.

Progress summary

Solved

A reader-posted calculation claims to disprove the conjecture with two explicit integers, but the claim has not been independently verified.

The conjecture asserts that every subunit index-ratio class contains at most one positive integer. Brahim Mittou introduced these classes and stated the conjecture in a 20252025 preprint, which records no general proof.

Posted attempt

A complete counterexample is claimed: 12251225 and 30253025 allegedly have the same subunit ratio 108/481108/481, and multiplying both by Q2Q^2 is claimed to produce infinitely many further nonunique classes. The calculation has not been independently verified.

Current status (as of August 2026): The conjecture has a posted but unverified complete counterexample; absent verification, the general claim remains mathematically unsettled.

Sources
Sources & referencesView supporting material

Primary source

Brahim Mittou, “A New Classification of Positive Integers Via New Divisor Functions”, arXiv:2509.08844 (2025).

Solutions 1

Counterexample

Complete counterexample and infinitely many distinct nonunique subunit classes.

For increasing positive divisors d1<<dτ(n)d_1<\cdots<d_{\tau(n)}, let

O(n)=j odddj,E(n)=j evendj,R(n)=E(n)/O(n).O(n)=\sum_{j\text{ odd}}d_j,\qquad E(n)=\sum_{j\text{ even}}d_j,\qquad R(n)=E(n)/O(n).

The distinct squares 1225=52721225=5^2\cdot7^2 and 3025=521123025=5^2\cdot11^2 have ordered divisor lists

Div(1225)=(1,5,7,25,35,49,175,245,1225),\operatorname{Div}(1225)=(1,5,7,25,35,49,175,245,1225), Div(3025)=(1,5,11,25,55,121,275,605,3025).\operatorname{Div}(3025)=(1,5,11,25,55,121,275,605,3025).

Therefore

R(1225)=3241443=108481=7563367=R(3025)<1.R(1225)=\frac{324}{1443}=\frac{108}{481}=\frac{756}{3367}=R(3025)<1.

Thus 12251225 and 30253025 are distinct members of G108/481G_{108/481}, disproving uniqueness.

In fact infinitely many different subunit classes are nonunique. Put t=108/481t=108/481. For every prime Q>3025Q>3025, the divisors of each mQ2mQ^2, with m{1225,3025}m\in\{1225,3025\}, occur in three consecutive blocks

Div(m),QDiv(m),Q2Div(m).\operatorname{Div}(m),\quad Q\operatorname{Div}(m),\quad Q^2\operatorname{Div}(m).

Each base list has nine divisors, so parity reverses in the middle block. Hence both distinct squares 1225Q21225Q^2 and 3025Q23025Q^2 have the same ratio

TQ(t)=t(Q2+1)+QQ2+1+Qt<1.T_Q(t)=\frac{t(Q^2+1)+Q}{Q^2+1+Qt}<1.

For distinct eligible primes Q,SQ,S,

TQ(t)TS(t)=(QS)(t21)(QS1)(Q2+Qt+1)(S2+St+1)0.T_Q(t)-T_S(t)=\frac{(Q-S)(t^2-1)(QS-1)}{(Q^2+Qt+1)(S^2+St+1)}\neq0.

Consequently infinitely many distinct subunit ratio classes contain at least two integers.

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Shivam Patel ·