Conversational QA Dataset Generation with Answer Revision

Conversational question--answer generation is a task that automatically generates a large-scale conversational question answering dataset based on input passages. In this paper, we introduce a novel framework that extracts question-worthy phrases from a passage and then generates corresponding questions considering previous conversations. In particular, our framework revises the extracted answers after generating questions so that answers exactly match paired questions. Experimental results show that our simple answer revision approach leads to significant improvement in the quality of synthetic data. Moreover, we prove that our framework can be effectively utilized for domain adaptation of conversational question answering.Comment: COLING 202

Toric Richardson varieties of Catalan type and Wedderburn-Etherington numbers

We associate a complete non-singular fan with a polygon triangulation. Such a fan appears from a certain toric Richardson variety, called of Catalan type introduced in this paper. A toric Richardson variety of Catalan type is a Fano Bott manifold. We show that toric Richardson varieties of Catalan type are classified up to isomorphism in terms of unordered binary trees. In particular, the number of isomorphism classes of $n$-dimensional toric Richardson varieties of Catalan type is the $(n+1)$th Wedderburn--Etherington number

Toric Schubert varieties and directed Dynkin diagrams

A flag variety is a homogenous variety $G/B$ where $G$ is a simple algebraic group over the complex numbers and $B$ is a Boel subgroup of $G$. A Schubert variety $X_w$ is a subvariety of $G/B$ indexed by an element $w$ in the Weyl group of $G$. It is called toric if it is a toric variety with respect to the maximal torus of $G$ in $B$. In this paper, we associate an edge-labeled digraph $\mathcal{G}_w$ with a toric Schubert variety $X_w$ and classify toric Schubert varieties up to isomorphism. We also give a simple criterion of when a toric Schubert variety $X_w$ is (weak) Fano in terms of $\mathcal{G}_w$. Finally, we discuss whether toric Schubert varieties can be distinguished by their integral cohomology rings up to isomorphism and show that this is the case when $G$ is of simply-laced type

On Schubert varieties of complexity one

Let $B$ be a Borel subgroup of $\mathrm{GL}_n(\mathbb{C})$ and $\mathbb{T}$ a maximal torus contained in $B$. Then $\mathbb{T}$ acts on $\mathrm{GL}_{n}(\mathbb{C})/B$ and every Schubert variety is $\mathbb{T}$-invariant. We say that a Schubert variety is of complexity $k$ if a maximal $\mathbb{T}$-orbit in $X_w$ has codimension $k$. In this paper, we discuss topology, geometry, and combinatorics related to Schubert varieties of complexity one.Comment: 24 pages, 4 figure

Is the mechanism of synchronous cardiocerebral infarction (CCI) different from that of metachronous CCI?

Background Cardiocerebral infarction (CCI) is the simultaneous occurrence of acute ischemic stroke (AIS) and myocardial infarction (MI) at the same time (synchronous), or one after another (metachronous). This study aimed to investigate the differences in the underlying mechanisms between synchronous and metachronous CCI. Methods This study analyzed patients with AIS registered in the Clinical Research Collaboration for Stroke in Korea Prospective Registry at a single Stroke Center from January 2019 to December 2022. Patients with synchronous and metachronous CCI (MI within 72 hours after AIS) were included. Severity at admission and modified Rankin Scale scores 3 months after treatment were assessed. Results Among 3,319 AIS patients, 12 (0.36%) were diagnosed with acute CCI (male, 8; mean age, 69.6±14.0 years). Of these, six (0.18%) had synchronous CCI, while the other six had metachronous CCI. The synchronous CCI group exhibited lower neurological severity at admission than the metachronous CCI group (median National Institutes of Health Stroke Scale, 3.5 vs. 12.5). Among the 12 patients, seven (58%) had ST-elevation myocardial infarction (STEMI), with five (83%) of the synchronous CCI cases presenting as STEMI. Two cases of new-onset atrial fibrillation occurred exclusively in patients with synchronous CCI. Also, one case with synchronous CCI had a thrombus in the left ventricle. Conclusion Acute CCI is rare and manifests with varying degrees of severity. Our study suggests that AIS in synchronous CCI may be secondary to embolism caused by a preceding MI. In contrast, metachronous CCI exhibits diverse mechanisms, including secondary myocardial injury resulting from a preceding severe AIS