Expert-authored, closed-ended problems spanning graduate-level material through research-frontier questions. Each item is independently verified and evaluated against current reasoning models before release.
Each item is authored by a domain expert, filtered against frontier models, and verified by a second expert before it enters the set.
A specific result from current literature in the author's discipline.
domain expertThe result becomes a closed-ended question; the machinery it depends on is stated in the prompt.
domain expertThe strongest available reasoning models attempt every item before release.
frontier modelsA second expert confirms the unique answer without seeing the author's derivation.
independent expertEach item is authored to one band. Sets are composed to a specified mix of subject and band. Every band passes the same solver filter—items current models solve reliably are removed; Band C sets the bar higher still and requires an outright incorrect answer.
Graduate level. Authored or verified by experts at or above the caliber of those behind Humanity's Last Exam; problems at graduate level.
Expert level. Long, difficult tasks drawn from domain experts' professional workflows; close to the research frontier.
Frontier level. Retained only if the strongest reasoning models available at authoring time answer incorrectly. Re-filtered as stronger models are released.
Four items from Bands A and B, shown in full. Answers are withheld; each resolves to a single value or statement a blind second expert can verify.
Given: A commercial HY zeolite (faujasite Y, $\mathrm{Si/Al}=15$) is desilicated in aqueous $\mathrm{NaOH}$ at increasing severity to give HY-parent and HY-strong. After washing to $\mathrm{pH}=8$, drying, and calcining in dry air at $550\,{}^{\circ}\mathrm{C}$:
In-situ IR spectroscopy at $170\,{}^{\circ}\mathrm{C}$ in $\mathrm{H_2O}$-saturated He after He pretreatment at $350\,{}^{\circ}\mathrm{C}$. Two bulky bases that cannot enter intact faujasite micropores are dosed separately:
Observed on HY-strong:
Task: Identify the predominant structural identity of the new $500\,{}^{\circ}\mathrm{C}$ acid sites in HY-strong that are external or mesopore-accessible and implicated in levulinic acid selectivity. Provide one chemically specific site description.
Consider the one-dimensional motion of an uncharged spin-$\frac{1}{2}$ particle with magnetic moment $\mu = -\frac{2\mu_0}{\hbar}\,s$. The particle is confined in an infinite square well extending from $x = -L$ to $x = L$. In region I $(x < 0)$ there is a uniform magnetic field $B = B_0\,e_z$ along the $z$ direction, and in region II $(x > 0)$ there is a uniform magnetic field $B = B_0\,e_x$ of the same magnitude pointing in the $x$ direction; $e_x$, $e_z$ are the unit vectors along $x$ and $z$.
Radial two-channel scattering is described by a matrix Schrödinger equation whose potential $V(r)$ is a real symmetric matrix function, taken short-ranged and allowed a centrifugal term. The Jost matrix is the transposed $r\to0$ limit of the matrix solution carrying plane-wave asymptotics at infinity; allowing for a centrifugal singularity $V(r\to0)\to r^{-2}\nu(\nu-1)$ at the origin it reads $F(E)=\lim_{r\to0} f^{t}(r,E)\,r^{\nu}/(2\nu-1)!!$ with $f(r\to\infty)\to\exp(i\sqrt{E}\,r)$. The scattering matrix $S(E)$ is the matrix coefficient in the solution $\psi(r,E)$ that vanishes at the origin and carries an outgoing plane wave at infinity, $\psi(r\to\infty,E)\to \exp(il\pi/2-i\sqrt{E}\,r)-\exp(-il\pi/2+i\sqrt{E}\,r)\,S(E)$, with $V(r\to\infty)\to r^{-2}l(l-1)$. Call a matrix nontrivially coupled when no constant similarity transformation brings it to diagonal form.
Which of the following are true? List the numbers of all correct statements.
A bosonic integer quantum Hall state at filling $\nu=2$ is characterised by the K-matrix $\sigma_x=\begin{pmatrix}0&1\\1&0\end{pmatrix}$. Suppose instead that the bosons forming this state are themselves Cooper pairs of composite fermions, each composite fermion having two flux quanta bound to it.
Write down the K-matrix of the fractional state that results.
Each item ships with its unique answer, the expert derivation, subject and difficulty labels, and the solver runs that qualified it for its band.
Specify subjects and difficulty bands; the set is authored to that mix.
When a stronger model is released, the set is re-run against it and items that no longer fail are flagged.
Repository-level tasks with a runnable environment and a concrete artifact contract. The submitted code is evaluated by an executable test suite.
Multi-step assignments modeled on complete professional engagements, with realistic evidence, tools, intermediate state, and graded deliverables.
Runnable research environments in which an AI system iterates on a working method. The submitted method is then re-executed on a sealed split.