The E6 normal forms: semisimple deformations, geometry, DT invariants, and the E6,∞ order
Abstract
We study the completed Jacobi algebras of x3+xy3+p(y) for ordyp=n≥4. The explicit normal-form morsification, the filtered length and centre proofs, and the cyclic terminal identities give finite free semisimple deformations. For every parameter of finite order we construct a polynomial curve neighbourhood and a local projective small contraction; the resulting geometric GV and Donaldson--Thomas calculations identify the block multiplicities. The one-dimensional limit E6,∞ is studied separately as an order: we determine its normalization, conductor, radical-idealizer chain, and maximal overorders. The canonical chain yields a nine-dimensional finite quotient whose Ringel dual is isomorphic to its opposite. An expanded construction gives a choice-independent $22$-dimensional quotient and a $40$-dimensional Ringel dual; a corner quotient relates the two finite constructions. The length and centre formulas are proved by a filtered comparison with a homogeneous matrix order and by terminal identities at the exceptional endpoint.
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BibTeX
@misc{pan2026normal,
title = {{The $E_6$ normal forms: semisimple deformations, geometry, DT invariants, and the $E_6,\infty$ order}},
author = {Shengyong Pan},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.13745},
eprint = {2610.13745},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.13745},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The E_6 normal forms: semisimple deformations, geometry, DT invariants, and the E_6,∞ order
AU - Shengyong Pan
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2610.13745
UR - https://arxiv.org/abs/2610.13745
AB - We study the completed Jacobi algebras of x^3+xy^3+p(y) for ord_yp=n≥4. The explicit normal-form morsification, the filtered length and centre proofs, and the cyclic terminal identities give finite free semisimple deformations. For every parameter of finite order we construct a polynomial curve neighbourhood and a local projective small contraction; the resulting geometric GV and Donaldson--Thomas calculations identify the block multiplicities. The one-dimensional limit E_6,∞ is studied separately as an order: we determine its normalization, conductor, radical-idealizer chain, and maximal overorders. The canonical chain yields a nine-dimensional finite quotient whose Ringel dual is isomorphic to its opposite. An expanded construction gives a choice-independent $22$-dimensional quotient and a $40$-dimensional Ringel dual; a corner quotient relates the two finite constructions. The length and centre formulas are proved by a filtered comparison with a homogeneous matrix order and by terminal identities at the exceptional endpoint.
ER -