Explicit Deformations of Algebras

Find explicit deformations from curvilinear algebras to monomial algebras.

Notability: Solid result
Solved: No
Contributor: Gergely Berczi
Field: Algebraic Geometry

About the problem

The study of deformations of Artinian algebras is central to the geometry of the Hilbert scheme of points, $\mathrm{Hilb}^k(\mathbb{C}^n)$. The curvilinear component $\mathrm{CHilb}_0^k(\mathbb{C}^n)$ plays a distinguished role: it parametrizes subschemes that are locally isomorphic to $\mathrm{Spec}(k[t]/(t^k))$ inside $\mathbb{C}^n$.

It is known that every such ideal is the deformation of the curvilinear ideal of the same dimension, but the proof is essentially nonconstructive. Such constructions would be useful for various applications. This problem is to provide an explicit deformation for a specific monomial algebra. The author expects that a solution to this problem would point toward a general strategy for constructing such deformations, which is the true target of this problem.

Warm-up: we ask for an explicit deformation to a simpler algebra, where the solution is known.

Full write-up

Attempts by AI

We have evaluated the following models on this problem. “Warm-up” refers to an easier variant of the problem with a known solution.

Model
Problem
Solved
Logs
GPT-5.2 Pro
Warm-up
Yes
GPT-5.2 Pro
Full Problem
No
Gemini 3 Deep Think
Full Problem
No

AI Prompts

Warm-up

Work over a field $k$ of characteristic $0$. Construct an explicit flat one-parameter deformation from the algebra $k[t]/(t^3)$ to the algebra \[ A \;=\; k[x,y]/(x,y)^2. \] Equivalently, you must give an ideal $I \subset k[x_1,\dots,x_s,\epsilon]$ (for some $s\ge 2$) such that the family \[ \mathcal{A} \;=\; k[x_1,\dots,x_s,\epsilon]/I \] over $k[\epsilon]$ satisfies: \begin{enumerate} \item \textbf{Special fiber:} $\mathcal{A}\big|_{\epsilon=0} \cong A$. In particular, the specialization $I|_{\epsilon=0}$ must cut out an algebra isomorphic to $k[x,y]/(x,y)^2$ (it is allowed to use more generators $x_1,\dots,x_s$ as long as the fiber is isomorphic to $A$). \item \textbf{Generic fiber:} for $a \neq 0$, $\mathcal{A}\big|_{\epsilon=a} \cong k[t]/(t^3)$. \end{enumerate} \subsection*{Mandatory output format} Submit a Python/SymPy snippet that defines the polynomial ring variables and the ideal generators. \begin{itemize} \item You may choose any $s\ge 2$. Use variables named \texttt{x1},\dots,\texttt{xs} and \texttt{eps}. \item Define \texttt{x\_vars} as the tuple $(x_1,\dots,x_s)$ in the same order used in \texttt{I\_gens}. \item Provide the ideal generators as a Python list named \texttt{I\_gens} of SymPy expressions in the symbols \texttt{x1},\dots,\texttt{xs},\texttt{eps}. \item Coefficients must be integers only (no fractions, no floats, no extra parameters besides \texttt{eps}). \item Use only polynomial operations \texttt{+}, \texttt{-}, \texttt{*}, \texttt{**}; do not use division. \item Do not include any explanatory text outside the code block. \end{itemize} \subsection*{Exact skeleton you must output (fill in $s$ and \texttt{I\_gens}).} \begin{verbatim} import sympy as sp # choose s >= 2 x1, x2, eps = sp.symbols("x1 x2 eps") # extend as needed: x3, x4, ... x_vars = (x1, x2) # extend consistently I_gens = [ # polynomial generators in x1,x2,(x3,x4,...),eps with integer coefficients ] \end{verbatim}

Full problem

Work over a field $k$ of characteristic $0$. Construct an explicit flat one-parameter deformation from the curvilinear algebra $k[t]/(t^{22})$ to the monomial "spider" algebra \[ A \;=\; k[x,y,z]/(x^8,\;y^8,\;z^8,\;xy,\;xz,\;yz). \] Equivalently, you must give an ideal $I \subset k[x_1,\dots,x_s,\epsilon]$ (for some $s\ge 3$) such that the family \[ \mathcal{A} \;=\; k[x_1,\dots,x_s,\epsilon]/I \] over $k[\epsilon]$ satisfies: \begin{enumerate} \item \textbf{Special fiber:} $\mathcal{A}\big|_{\epsilon=0} \cong A$. In particular, the specialization $I|_{\epsilon=0}$ must cut out an algebra isomorphic to $k[x,y,z]/(x^8,y^8,z^8,xy,xz,yz)$ (it is allowed to use more generators $x_1,\dots,x_s$ as long as the fiber is isomorphic to $A$). \item \textbf{Generic fiber:} for $a \neq 0$, $\mathcal{A}\big|_{\epsilon=a} \cong k[t]/(t^{22})$. \end{enumerate} \subsection*{Mandatory output format} Submit a Python/SymPy snippet that defines the polynomial ring variables and the ideal generators. \begin{itemize} \item You may choose any $s\ge 3$. Use variables named \texttt{x1},\dots,\texttt{xs} and \texttt{eps}. \item Define \texttt{x\_vars} as the tuple $(x_1,\dots,x_s)$ in the same order used in \texttt{I\_gens}. \item Provide the ideal generators as a Python list named \texttt{I\_gens} of SymPy expressions in the symbols \texttt{x1},\dots,\texttt{xs},\texttt{eps}. \item Coefficients must be integers only (no fractions, no floats, no extra parameters besides \texttt{eps}). \item Use only polynomial operations \texttt{+}, \texttt{-}, \texttt{*}, \texttt{**}; do not use division. \item Do not include any explanatory text outside the code block. \end{itemize} \subsection*{Exact skeleton you must output (fill in $s$ and \texttt{I\_gens}).} \begin{verbatim} import sympy as sp # choose s >= 3 x1, x2, x3, eps = sp.symbols("x1 x2 x3 eps") # extend as needed: x4, x5, ... x_vars = (x1, x2, x3) # extend consistently I_gens = [ # polynomial generators in x1,x2,x3,(x4,...),eps with integer coefficients ] \end{verbatim}

Mathematician survey

The author assessed the problem as follows.

# of mathematicians highly familiar with the problem: a majority of those working on a specialized topic (≈10)
# of mathematicians who have made a serious attempt to solve the problem: 2–4
Rough guess of how long it would take an expert human to solve the problem: 3–12 months
Notability of a solution: a solid result in a subfield
A solution would be published: in a standard specialty journal
Likelihood of a solution generating more interesting math: fairly likely: the problem is rich enough that most solutions should open new avenues
Probability that the problem is solvable as stated: 80–95%