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arxiv: 1907.01229 · v1 · pith:5P23UKVUnew · submitted 2019-07-02 · 🧮 math.NT

Pairs of Pythagorean triangles with given catheti ratios

Pith reviewed 2026-05-25 11:07 UTC · model grok-4.3

classification 🧮 math.NT
keywords Pythagorean triplescatheti ratiosDiophantine equationsinfinitely many solutionsnon-similar trianglesright triangles
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The pith

For catheti ratios A/a and B/b with Aa ≠ Bb there exist infinitely many non-similar pairs of Pythagorean triangles satisfying the ratios.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper proves that for any fixed positive ratios A/a and B/b satisfying Aa ≠ Bb, the conditions that both (a, b, c) and (A, B, C) are Pythagorean triples yield infinitely many integer solutions in which the two triangles are not similar. A reader cares because this turns the search for such pairs from a problem that might have only isolated examples into one that always produces an infinite family under a simple inequality. The argument proceeds by parametrizing the triples, substituting the ratio conditions, and showing that the resulting Diophantine system has infinitely many solutions precisely when the product condition holds.

Core claim

There are infinitely many essentially different (non-similar) pairs of Pythagorean triangles (a, b, c), (A, B, C) satisfying given proportions A/a, B/b, provided that Aa ≠ Bb.

What carries the argument

The Diophantine system formed by the two Pythagorean equations together with the two fixed-ratio equations, shown to possess infinitely many solutions once Aa ≠ Bb.

If this is right

  • Any ratios meeting the product inequality produce infinitely many distinct pairs.
  • The triangles in each pair can be taken primitive or with arbitrary common factors.
  • Similarity is ruled out because the side ratios between the two triangles differ.
  • The infinitude holds for both primitive and non-primitive triples.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • When Aa = Bb the same system may possess only finitely many solutions.
  • The method could be adapted to produce infinite families with additional constraints such as equal perimeters or equal areas.
  • Analogous infinitude statements might hold for triples of triangles or for higher-dimensional Pythagorean objects.

Load-bearing premise

The chosen ratios A/a and B/b are such that the Diophantine system admits integer solutions at all.

What would settle it

An explicit pair of positive ratios A/a, B/b with Aa ≠ Bb for which the corresponding system of equations has only finitely many positive integer solutions a, b, c, A, B, C.

read the original abstract

In this note we investigate the problem of finding pairs of Pythagorean triangles $(a, b, c), (A, B, C)$, with given catheti ratios $A/a, B/b$. In particular, we prove that there are infinitely many essentially different ("non-similar") pairs of Pythagorean triangles $(a, b, c), (A, B, C)$ satisfying given proportions, provided that $Aa\neq Bb$.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The manuscript claims to prove that, for given positive real catheti ratios A/a and B/b, there exist infinitely many essentially different (non-similar) pairs of Pythagorean triangles (a,b,c) and (A,B,C) satisfying those ratios, provided Aa ≠ Bb.

Significance. If the central claim held with a corrected non-similarity condition, the result would supply a Diophantine construction for infinite families of non-similar Pythagorean pairs with prescribed leg ratios, which is of modest interest in elementary number theory. The manuscript supplies no machine-checked proofs or parameter-free derivations.

major comments (1)
  1. [Abstract] Abstract (and main theorem statement): the proviso 'provided that Aa ≠ Bb' does not guarantee non-similarity. Similarity holds precisely when A/a = B/b (i.e., aB = Ab). When A/a = B/b but a ≠ b, the triangles are similar yet Aa ≠ Bb is satisfied, so the stated condition includes similar pairs and fails to support the claim of 'essentially different (non-similar)' pairs. This is load-bearing for the central result.
minor comments (1)
  1. The abstract supplies no explicit parametric formulas or verification steps for the claimed solutions; the full text should include at least one concrete numerical example satisfying both Pythagorean equations simultaneously.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for identifying an important error in the statement of the non-similarity condition. We address the major comment below.

read point-by-point responses
  1. Referee: [Abstract] Abstract (and main theorem statement): the proviso 'provided that Aa ≠ Bb' does not guarantee non-similarity. Similarity holds precisely when A/a = B/b (i.e., aB = Ab). When A/a = B/b but a ≠ b, the triangles are similar yet Aa ≠ Bb is satisfied, so the stated condition includes similar pairs and fails to support the claim of 'essentially different (non-similar)' pairs. This is load-bearing for the central result.

    Authors: We agree that the condition Aa ≠ Bb does not guarantee non-similarity of the triangles. As the referee correctly notes, the triangles are similar precisely when A/a = B/b (equivalently aB = Ab). When A/a = B/b but a ≠ b, the pairs satisfy Aa ≠ Bb yet remain similar, so the stated proviso fails to exclude similar pairs. We will revise the abstract and the main theorem statement to replace the condition 'provided that Aa ≠ Bb' with the correct condition 'provided that A/a ≠ B/b'. This correction is necessary and will be incorporated in the revised manuscript. The underlying Diophantine construction appears to produce pairs satisfying the corrected non-similarity condition, so the central existence result should hold after the change. revision: yes

Circularity Check

0 steps flagged

No circularity; derivation uses external Diophantine machinery

full rationale

The paper claims to prove existence of infinitely many non-similar Pythagorean triangle pairs with prescribed catheti ratios A/a and B/b, under the condition Aa ≠ Bb. No equations, parameters, or constructions in the provided abstract reduce the target result to a self-definition, a fitted input renamed as prediction, or a load-bearing self-citation chain. The proof is described as resting on standard number-theoretic tools for solving the associated Diophantine system, which are independent of the specific infinitude claim being established. The condition Aa ≠ Bb is an explicit hypothesis rather than a derived or fitted quantity, and the non-similarity claim is presented as following from that hypothesis via external results. This is the normal case of a self-contained existence proof.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

Only the abstract is available, so the ledger records the minimal background needed to state the claim.

axioms (2)
  • standard math Pythagorean triples satisfy a² + b² = c² with a, b, c positive integers
    Invoked implicitly when the paper refers to Pythagorean triangles.
  • domain assumption The catheti ratios A/a and B/b are fixed positive reals
    Stated in the problem setup in the abstract.

pith-pipeline@v0.9.0 · 5589 in / 1356 out tokens · 30883 ms · 2026-05-25T11:07:58.287094+00:00 · methodology

discussion (0)

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