Sampei Usui

493 total citations
32 papers, 192 citations indexed

About

Sampei Usui is a scholar working on Geometry and Topology, Mathematical Physics and Algebra and Number Theory. According to data from OpenAlex, Sampei Usui has authored 32 papers receiving a total of 192 indexed citations (citations by other indexed papers that have themselves been cited), including 29 papers in Geometry and Topology, 22 papers in Mathematical Physics and 2 papers in Algebra and Number Theory. Recurrent topics in Sampei Usui's work include Algebraic Geometry and Number Theory (24 papers), Advanced Algebra and Geometry (16 papers) and Homotopy and Cohomology in Algebraic Topology (11 papers). Sampei Usui is often cited by papers focused on Algebraic Geometry and Number Theory (24 papers), Advanced Algebra and Geometry (16 papers) and Homotopy and Cohomology in Algebraic Topology (11 papers). Sampei Usui collaborates with scholars based in Japan and United States. Sampei Usui's co-authors include Kazuya Katô, Chikara Nakayama, Kazuya Kato, Kazuya Kato and Masa-Hiko Saito and has published in prestigious journals such as Duke Mathematical Journal, Annales Scientifiques de l École Normale Supérieure and Tohoku Mathematical Journal.

In The Last Decade

Sampei Usui

28 papers receiving 155 citations

Peers — A (Enhanced Table)

Peers by citation overlap · career bar shows stage (early→late) cites · hero ref

Name	h						Papers	Cites
Sampei Usui Japan	8	188	148	27	21	15	32	192
D. S. Nagaraj India	8	180 1.0×	148 1.0×	19 0.7×	10 0.5×	13 0.9×	30	184
Donghoon Hyeon United States	7	167 0.9×	94 0.6×	20 0.7×	23 1.1×	28 1.9×	16	167
Sławomir Cynk Poland	9	155 0.8×	112 0.8×	16 0.6×	13 0.6×	12 0.8×	22	159
Alessandro Verra Italy	10	198 1.1×	139 0.9×	39 1.4×	18 0.9×	32 2.1×	29	207
Dorette Pronk Canada	6	140 0.7×	149 1.0×	74 2.7×	17 0.8×	8 0.5×	17	166
Paltin Ionescu Romania	6	178 0.9×	93 0.6×	19 0.7×	38 1.8×	32 2.1×	11	181
G. K. Sankaran United Kingdom	8	174 0.9×	158 1.1×	41 1.5×	16 0.8×	7 0.5×	35	191
Marian Aprodu Romania	8	146 0.8×	83 0.6×	54 2.0×	37 1.8×	24 1.6×	30	155
賢治深谷	2	218 1.2×	173 1.2×	18 0.7×	29 1.4×	15 1.0×	2	229
Jack Morava United States	5	117 0.6×	114 0.8×	48 1.8×	8 0.4×	16 1.1×	19	136

Countries citing papers authored by Sampei Usui

Since Specialization

Citations

This map shows the geographic impact of Sampei Usui's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by Sampei Usui with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites Sampei Usui more than expected).

Fields of papers citing papers by Sampei Usui

Since Specialization

Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by Sampei Usui. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by Sampei Usui. The network helps show where Sampei Usui may publish in the future.

Co-authorship network of co-authors of Sampei Usui

This figure shows the co-authorship network connecting the top 25 collaborators of Sampei Usui. A scholar is included among the top collaborators of Sampei Usui based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with Sampei Usui. Sampei Usui is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

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20 of 20 papers shown

Katô, Kazuya, Chikara Nakayama, & Sampei Usui. (2019). Classifying spaces of degenerating mixed Hodge structures, I: Borel–Serre spaces. Advanced studies in pure mathematics. 187–222.

Katô, Kazuya & Sampei Usui. (2019). Borel-Serre Spaces and Spaces of SL(2)-Orbits. Advanced studies in pure mathematics. 321–382. 2 indexed citations

Kato, Kazuya, Chikara Nakayama, & Sampei Usui. (2014). Néron models for admissible normal functions. Proceedings of the Japan Academy Series A Mathematical Sciences. 90(1).

Katô, Kazuya, Chikara Nakayama, & Sampei Usui. (2013). Classifying spaces of degenerating mixed Hodge structures, III: Spaces of nilpotent orbits. Journal of Algebraic Geometry. 22(4). 671–772. 4 indexed citations

Katô, Kazuya, Chikara Nakayama, & Sampei Usui. (2011). Analyticity of the closures of some Hodge theoretic subspaces. Proceedings of the Japan Academy Series A Mathematical Sciences. 87(9). 3 indexed citations

Katô, Kazuya, Chikara Nakayama, & Sampei Usui. (2010). Log intermediate Jacobians. Proceedings of the Japan Academy Series A Mathematical Sciences. 86(4). 6 indexed citations

Katô, Kazuya, Chikara Nakayama, & Sampei Usui. (2010). Moduli of log mixed Hodge structures. Proceedings of the Japan Academy Series A Mathematical Sciences. 86(7). 7 indexed citations

Katô, Kazuya & Sampei Usui. (2009). Classifying Spaces of Degenerating Polarized Hodge Structures. (AM-169). Princeton University Press eBooks. 21 indexed citations

Usui, Sampei & Kazuya Kato. (2008). Classifying Spaces of Degenerating Polarized Hodge Structures.. 16 indexed citations

10.

Katô, Kazuya, Chikara Nakayama, & Sampei Usui. (2007). 𝑆𝐿(2)-orbit theorem for degeneration of mixed Hodge structure. Journal of Algebraic Geometry. 17(3). 401–479. 17 indexed citations

11.

Usui, Sampei. (2001). Recovery of vanishing cycles by log geometry. Tohoku Mathematical Journal. 53(1). 12 indexed citations

12.

Usui, Sampei. (2000). Torelli type problems. OUKA (Osaka University Knowledge Archive) (Osaka University). 13. 17–38. 2 indexed citations

13.

Usui, Sampei. (1999). Recovery of Vanishing Cycles by Log Geometry : Case of Several Variables. Kyoto University Research Information Repository (Kyoto University). 135–144. 5 indexed citations

14.

Usui, Sampei. (1993). A numerical criterion for admissibility of semi-simple elements. Tohoku Mathematical Journal. 45(4). 6 indexed citations

15.

Usui, Sampei. (1992). Period maps and their extensions. OUKA (Osaka University Knowledge Archive) (Osaka University). 803(803). 26–47. 1 indexed citations

16.

Usui, Sampei. (1991). Mixed Torelli problem for Todorov surfaces. Osaka Journal of Mathematics. 28(3). 697–735. 4 indexed citations

17.

Usui, Sampei. (1989). Type I degeneration of Kunev surfaces. Astérisque. 185–243. 2 indexed citations

18.

Usui, Sampei. (1984). Variation of mixed Hodge structure arising from family of logarithmic deformations II: Classifying space. Duke Mathematical Journal. 51(4). 27 indexed citations

19.

Usui, Sampei. (1977). Local Torelli theorem for some non-singular weighted complete intersections. Kyoto University Research Information Repository (Kyoto University). 723–734. 1 indexed citations

20.

Usui, Sampei, et al.. (1977). On numerical positivity of ample vector bundles with additional condition. Kyoto journal of mathematics. 17(1). 3 indexed citations

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

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