Non-nilpotent Leibniz algebras with one-dimensional derived subalgebra
Pith reviewed 2026-05-24 08:13 UTC · model grok-4.3
The pith
Every non-nilpotent non-Lie Leibniz algebra with one-dimensional derived subalgebra is isomorphic to L_n, the direct sum of a fixed two-dimensional algebra and an abelian algebra.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We prove that such an algebra is isomorphic to the direct sum of the two-dimensional non-nilpotent non-Lie Leibniz algebra and an abelian algebra. We denote it by L_n, where n equals the dimension. We also determine the Lie algebra of derivations, the Lie group of automorphisms, and the Leibniz algebra of biderivations of L_n. Finally we solve the coquecigrue problem for L_n by integrating it into a Lie rack.
What carries the argument
The algebra L_n, defined as the direct sum of the two-dimensional non-nilpotent non-Lie Leibniz algebra with an abelian algebra of dimension n-2.
If this is right
- The derivation algebra of L_n can be described explicitly as a Lie algebra.
- The automorphism group of L_n is a Lie group whose structure follows from the direct-sum decomposition.
- The biderivation algebra of L_n forms a Leibniz algebra that can be computed directly from the form of L_n.
- L_n admits an integration into a Lie rack that solves the coquecigrue problem for these algebras.
Where Pith is reading between the lines
- The reduction to a standard non-abelian summand plus abelian part may extend to Leibniz algebras whose derived subalgebra has dimension two or three.
- The explicit Lie-rack integration supplies a geometric model that could be used to study representations or actions associated with L_n.
- Similar direct-sum classifications might simplify the study of cohomology or deformations for this family.
Load-bearing premise
The algebra is non-nilpotent, non-Lie, and has derived subalgebra of dimension exactly one over a field of characteristic not 2.
What would settle it
An explicit example of a non-nilpotent non-Lie Leibniz algebra with one-dimensional derived subalgebra that is not isomorphic to L_n for its dimension would disprove the classification.
read the original abstract
In this paper we study non-nilpotent non-Lie Leibniz $\mathbb{F}$-algebras with one-dimensional derived subalgebra, where $\mathbb{F}$ is a field with $\operatorname{char}(\mathbb{F}) \neq 2$. We prove that such an algebra is isomorphic to the direct sum of the two-dimensional non-nilpotent non-Lie Leibniz algebra and an abelian algebra. We denote it by $L_n$, where $n=\dim_{\mathbb{F}} L_n$. This generalizes the result found in [11], which is only valid when $\mathbb{F}=\mathbb{C}$. Moreover, we find the Lie algebra of derivations, its Lie group of automorphisms and the Leibniz algebra of biderivations of $L_n$. Eventually, we solve the coquecigrue problem for $L_n$ by integrating it into a Lie rack.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript proves a classification theorem stating that every non-nilpotent non-Lie Leibniz algebra L over a field F with char(F) ≠ 2 and dim L' = 1 is isomorphic to L_n, the direct sum of the unique 2-dimensional non-nilpotent non-Lie Leibniz algebra and an (n-2)-dimensional abelian algebra. It additionally computes the derivation algebra, automorphism group, biderivation algebra of L_n and integrates L_n into a Lie rack to solve the coquecigrue problem.
Significance. If the classification holds, the result extends the known classification over ℂ to arbitrary fields of characteristic not 2 and supplies explicit structural data (derivations, automorphisms, biderivations, and rack integration) that can be used directly in further work on Leibniz algebras and their geometric realizations.
Simulated Author's Rebuttal
We thank the referee for the positive assessment of the manuscript, the recognition of its significance in extending the classification from ℂ to arbitrary fields of characteristic not 2, and the recommendation to accept.
Circularity Check
No significant circularity
full rationale
The paper establishes a classification theorem by direct algebraic case analysis on the multiplication table and derived subalgebra of non-nilpotent non-Lie Leibniz algebras over fields of characteristic not 2. The isomorphism to the direct sum of the fixed 2-dimensional algebra and an abelian summand follows from exhaustive casework on basis elements and the one-dimensionality of L', using only the Leibniz identity and the stated assumptions; no parameter fitting, self-referential definitions, or load-bearing self-citations reduce the central claim to its own inputs. The cited prior result for ℂ is external and the present proof extends it independently.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption The base field has characteristic not equal to 2.
- standard math Leibniz algebra axioms: bilinear product satisfying the Leibniz identity.
Reference graph
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