Finite Groups Isospectral to Simple Groups

Maria A. Grechkoseeva , Victor D. Mazurov , Wujie Shi , Andrey V. Vasil’ev , Nanying Yang

Communications in Mathematics and Statistics ›› 2023, Vol. 11 ›› Issue (2) : 169 -194.

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Communications in Mathematics and Statistics ›› 2023, Vol. 11 ›› Issue (2) : 169 -194. DOI: 10.1007/s40304-022-00288-5
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Finite Groups Isospectral to Simple Groups

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Abstract

The spectrum of a finite group is the set of element orders of this group. The main goal of this paper is to survey results concerning recognition of finite simple groups by spectrum, in particular, to list all finite simple groups for which the recognition problem is solved.

Keywords

Finite group / Simple group / Element order / Spectrum / Recognition by spectrum

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Maria A. Grechkoseeva, Victor D. Mazurov, Wujie Shi, Andrey V. Vasil’ev, Nanying Yang. Finite Groups Isospectral to Simple Groups. Communications in Mathematics and Statistics, 2023, 11(2): 169-194 DOI:10.1007/s40304-022-00288-5

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References

[1]

Adyan, S.I.: Investigations on the Burnside problem and questions connected with it. In: Algebra, Mathematical Logic, Number Theory, Topology, pp. 179–205, Proc. Steklov Inst. Math., (1986)

[2]

Aleeva MR. On composition factors of finite groups having the same set of element orders as the group $U_3 (q)$. Siberian Math. J.. 2002, 43 2 195-211

[3]

Aleeva MR. On finite simple groups with the set of element orders as in a Frobenius group or a double Frobenius group. Math. Notes. 2003, 73 3 299-313

[4]

Alekseeva OA. Quasirecognizability by the set of element orders for groups $^3D_4(q)$, for $q$ even. Algebra Logic. 2006, 45 1 1-11

[5]

Alekseeva OA, Kondrat’ev AS. Quasirecognition of one class of finite simple groups by the set of element orders. Siberian Math. J.. 2003, 44 2 195-207

[6]

Alekseeva OA, Kondrat’ev AS. Quasirecognizability by the set of element orders of the groups $^3D_4(q)$ and $F_4(q)$, for $q$ odd. Algebra Logic. 2005, 44 5 287-301

[7]

Alekseeva OA, Kondrat’ev AS. Recognizability of the groups $^2{D}_p(3)$ with $p$ odd prime by spectrum. Trudy Inst. Mat. Mekh. UrO RAN. 2008, 14 4 3-11

[8]

Alekseeva OA, Kondrat’ev AS. On recognizability of some finite simple orthogonal groups by spectrum. Proc. Steklov Inst. Math.. 2009, 266 suppl. 1 S10-S23

[9]

Alekseeva OA, Kontrat’ev AS. On recognizability of the group $E_8(q)$ by the set of orders of element. Ukrainian Math. J.. 2002, 54 7 1200-1206

[10]

Bang AS. Taltheoretiske Undersøgelser. Tidsskrift Math.. 1886, 4 70–80 130-137

[11]

Brandl R, Shi W. Finite groups whose element orders are consecutive integers. J. Algebra. 1991, 143 2 388-400

[12]

Brandl R, Shi W. A characterization of finite simple groups with abelian Sylow $2$-subgroups. Ricerche Mat.. 1993, 42 1 193-198

[13]

Brandl R, Shi W. The characterization of $PSL(2, q)$ by its element orders. J. Algebra. 1994, 163 1 109-114

[14]

Buturlakin AA. Spectra of finite linear and unitary groups. Algebra Logic. 2008, 47 2 91-99

[15]

Buturlakin AA. Spectra of finite symplectic and orthogonal groups. Siberian Adv. Math.. 2011, 21 3 176-210

[16]

Buturlakin AA. Spectra of groups $E_8(q)$. Algebra Logic. 2018, 57 1 1-8

[17]

Cao H, Chen G, Grechkoseeva MA, Mazurov VD, Shi W, Vasil’ev AV. Recognition of the finite simple groups $F_4(2^m)$ by the spectrum. Siberian Math. J.. 2004, 45 6 1031-1035

[18]

Chen, G.: On Thompson’s Conjecture – For sporadic groups. In: Proc. China Assoc. Sci. and Tech. First Academic Annual Meeting of Youths, pp. 1–6, Chinese Sci. and Tech. Press, Beijing (1992). (in Chinese)

[19]

Chen, G., Mazurov, V.D., Shi, W., Vasil’ev, A., Zhurtov, A.Kh.: Recognition of the finite almost simple groups $PGL_2(q)$ by their spectrum. J. Group Theory 10(1), 71–85 (2007)

[20]

Conway JH, Curtis RT, Norton SP, Parker RA, Wilson RA. Atlas of finite groups. 1985 Oxford: Clarendon Press

[21]

Deng H, Shi W. The characterization of Ree groups $^2F_4(q)$ by their element orders. J. Algebra. 1999, 217 1 180-187

[22]

Gorenstein, D., Lyons, R., Solomon, R.: The classification of the finite simple groups. Number 3 (Mathematical Surveys and Monographs, vol. 40.3), Amer. Math. Soc., Providence, RI (1998)

[23]

Gorshkov IB. Characterization of groups with non-simple socle. Mediterr. J. Math.. 2022, 19 56

[24]

Gorshkov IB. Recognizability of alternating groups by spectrum. Algebra Logic. 2013, 52 1 41-45

[25]

Gorshkov IB. Recognizability of symmetric groups by spectrum. Algebra Logic. 2014, 53 6 450-457

[26]

Gorshkov IB. On Thompson’s conjecture for finite simple groups. Comm. Algebra. 2019, 47 12 5192-5206

[27]

Gorshkov IB, Grishkov AN. On recognition by spectrum of symmetric groups. Sib. Elektron. Mat. Izv.. 2016, 13 111-121

[28]

Gorshkov IB, Maslova NV. The group $J_4\times J_4$ is recognizable by spectrum. J. Algebra Appl.. 2021, 20 4 2150061

[29]

Grechkoseeva MA. Recognition by spectrum for finite linear groups over fields of characteristic $2$. Algebra Logic. 2008, 47 4 229-241

[30]

Grechkoseeva MA. Quasirecognizability of simple unitary groups over fields of even order. Sib. Elektron. Mat. Izv.. 2010, 7 435-444

[31]

Grechkoseeva MA. On element orders in covers of finite simple classical groups. J. Algebra. 2011, 339 304-319

[32]

Grechkoseeva MA. On element orders in covers of finite simple groups of Lie type. J. Algebra Appl.. 2015, 14 1550056

[33]

Grechkoseeva MA. On spectra of almost simple groups with symplectic or orthogonal socle. Siberian Math. J.. 2016, 57 4 582-588

[34]

Grechkoseeva MA. On orders of elements of finite almost simple groups with linear or unitary socle. J. Group Theory. 2017, 20 6 1191-1222

[35]

Grechkoseeva MA. On spectra of almost simple extensions of even-dimensional orthogonal groups. Siberian Math. J.. 2018, 59 4 623-640

[36]

Grechkoseeva MA. Orders of elements of finite almost simple groups. Algebra Logic. 2018, 56 6 502-505

[37]

Grechkoseeva MA, Lytkin DV. Almost recognizability by spectrum of finite simple linear groups of prime dimension. Siberian Math. J.. 2012, 53 4 645-655

[38]

Grechkoseeva MA, Shi W. On finite groups isospectral to finite simple unitary groups over fields of characteristic 2. Sib. Elektron. Mat. Izv.. 2013, 10 31-37

[39]

Grechkoseeva MA, Shi W, Vasil’ev AV. Recognition by spectrum for finite simple groups of Lie type. Front. Math. China. 2008, 3 2 275-285

[40]

Grechkoseeva MA, Skresanov SV. On element orders in covers of $L_4(q)$ and $U_4(q)$. Sib. Elektron. Mat. Izv.. 2020, 17 585-589

[41]

Grechkoseeva MA, Staroletov AM. Unrecognizability by spectrum of finite simple orthogonal groups of dimension nine. Sib. Elektron. Mat. Izv.. 2014, 11 921-928

[42]

Grechkoseeva MA, Vasil’ev AV. On the structure of finite groups isospectral to finite simple groups. J. Group Theory. 2015, 18 5 741-759

[43]

Grechkoseeva MA, Vasil’ev AV. On the prime graph of a finite group with unique nonabelian composition factor. Comm. Algebra. 2022

[44]

Grechkoseeva MA, Vasil’ev AV, Zvezdina MA. Recognition of symplectic and orthogonal groups of small dimensions by spectrum. J. Algebra Appl.. 2019, 18 12 1950230

[45]

Grechkoseeva MA, Zvezdina MA. On spectra of automorphic extensions of finite simple groups $F_4(q)$ and $^3D_4(q)$. J. Algebra Appl.. 2016, 15 9 1650168

[46]

Grechkoseeva MA, Zvezdina MA. On recognition of $L_4(q)$ and $U_4(q)$ by spectrum. Siberian Math. J.. 2020, 61 6 1039-1065

[47]

He, H.: Recognition by spectrum for the simple group $^2A_n(3)$ with disconnected prime graph. J. Chongqing Norm. Univ., Nat. Sci. 33(4), 57–60 (2016). (in Chinese)

[48]

He H, Shi W. Recognition of some finite simple groups of type ${D}_n(q)$ by spectrum. Int. J. Algebra Comput.. 2009, 19 5 681-698

[49]

He H, Shi W. A note on the adjacency criterion for the prime graph and characterization of $C_p(3)$. Algebra Colloq.. 2012, 19 3 553-562

[50]

Herzog, M., Longobardi, P., Maj, M.: Properties of finite and periodic groups determined by their element of orders (a survey). In: Group theory and computation, pp. 59–90, Indian Stat. Inst. Ser., Springer, Singapore (2018)

[51]

Higman G. Finite groups in which every element has prime power order. J. London Math. Soc.. 1957, 32 335-342

[52]

Khukhro, E.I., Mazurov, V.D.: (Eds.), Unsolved problems in group theory. The Kourovka notebook (2021), arXiv:1401.0300 [math.GR] (https://kourovka-notebook.org)

[53]

Kimmerle W, Luca F, Raggi-Cárdenas AG. Irreducible components and isomorphisms of the Burnside ring. J. Group Theory. 2008, 11 6 831-844

[54]

Kondrat’ev AS. On prime graph components of finite simple groups. Math. USSR-Sb.. 1990, 67 1 235-247

[55]

Kondrat’ev AS. Quasirecognition by the set of element orders of the groups $E_6(q)$ and $^2E_6(q)$. Siberian Math. J.. 2007, 48 6 1001-1018

[56]

Kondrat’ev AS. On the recognizability of finite simple orthogonal groups by the spectrum. II. Vladikavkaz. Mat. Zh.. 2009, 11 4 32-43

[57]

Kondrat’ev AS. Recognition by spectrum of the groups $^2D_{2^m+1}(3)$. Sci. China Ser. A. 2009, 52 2 293-300

[58]

Kondrat’ev AS. Recognizability by spectrum of $E_8(q)$. Trudy Inst. Mat. Mekh. UrO RAN. 2010, 16 3 146-149

[59]

Kondrat’ev AS, Mazurov VD. Recognition of alternating groups of prime degree from the orders of their elements. Siberian Math. J.. 2000, 41 2 294-302

[60]

Li H, Shi W. A characterization of some sporadic simple groups. J. Contemp. Math.. 1993, 14 2 105-113

[61]

Lipschutz S, Shi W. Finite groups whose element orders do not exceed twenty. Progr. Nat. Sci.. 2000, 10 1 11-21

[62]

Lucido MS. Prime graph components of finite almost simple groups. Rend. Semin. Mat. Univ. Padova. 1999, 102 1-22

[63]

Lucido MS, Moghaddamfar AR. Groups with complete prime graph connected components. J. Group Theory. 2004, 7 3 373-384

[64]

Lytkin YuV. On groups critical with respect to a set of natural numbers. Sib. Elektron. Mat. Izv.. 2013, 10 666-675

[65]

Lytkin YuV. Groups that are critical with respect to the spectra of alternating and sporadic groups. Siberian Math. J.. 2015, 56 1 101-106

[66]

Lytkin YuV. On finite groups isospectral to the group $U_3(3)$. Siberian Math. J.. 2017, 58 4 633-643

[67]

Lytkin YuV. On finite groups isospectral to the simple groups $S_4(q)$. Sib. Elektron. Mat. Izv.. 2018, 15 570-584

[68]

Lytkin YuV. On finite groups isospectral to the simple group $S_4(3)$. Sib. Elektron. Mat. Izv.. 2019, 16 1561-1566

[69]

Lytkina DV, Mazurov VD. Groups with given element orders. J. Sib. Fed. Univ. Math. Phys.. 2014, 7 2 191-203

[70]

Mazurov VD. Characterizations of finite groups by sets of orders of their elements. Algebra Logic. 1997, 36 1 23-32

[71]

Mazurov VD. Recognition of finite nonsimple groups by the set of orders of their elements. Algebra Logic. 1997, 36 3 182-192

[72]

Mazurov VD. Recognition of finite groups by a set of orders of their elements. Algebra Logic. 1998, 37 6 371-379

[73]

Mazurov VD. Recognition of finite simple groups $S_4(q)$ by their element orders. Algebra Logic. 2002, 41 2 93-110

[74]

Mazurov VD. Characterizations of groups by arithmetic properties. Algebra Colloq.. 2004, 11 1 129-140

[75]

Mazurov VD. Groups with a prescribed spectrum. Izv. Ural. Gos. Univ. Mat. Mekh.. 2005, 36 119-138

[76]

Mazurov VD. Unrecognizability by spectrum for a finite simple group $^3D_4(2)$. Algebra Logic. 2013, 52 5 400-403

[77]

Mazurov VD. 2-Frobenius groups isospectral to the simple group $U_3(3)$. Siberian Math. J.. 2015, 56 6 1108-1113

[78]

Mazurov VD. Finite simple groups unrecognizable by spectrum and the groups isospectral to them. Vladikavkaz. Mat. Zh.. 2015, 17 2 47-55

[79]

Mazurov VD, Chen G. Recognizability of the finite simple groups $L_4(2^m)$ and $U_4(2^m)$ by the spectrum. Algebra Logic. 2008, 47 1 49-55

[80]

Mazurov VD, Moghaddamfar AR. The recognition of the simple group $S_8(2)$ by its spectrum. Algebra Colloq.. 2006, 13 4 643-646

[81]

Mazurov VD, Moghaddamfar AR. Recognizing by spectrum for the automorphism groups of sporadic simple groups. Commun. Math. Stat.. 2015, 3 4 491-496

[82]

Mazurov, V.D., Ol’shanskii, A.Yu., Sozutov, A.I.: Infinite groups of finite period. Algebra Logic 54(2), 161–166 (2015)

[83]

Mazurov VD, Shi W. A note to the characterization of sporadic simple groups. Algebra Colloq.. 1998, 5 3 285-288

[84]

Mazurov VD, Shi W. On periodic groups with prescribed orders of elements. Sci. China Ser. A. 2009, 52 2 311-317

[85]

Mazurov VD, Shi W. A criterion of unrecognizability by spectrum for finite groups. Algebra Logic. 2012, 51 2 160-162

[86]

Mazurov VD, Xu M, Cao H. Recognition of the finite simple groups $L_3(2^m)$ and $U_3(2^m)$ by their element orders. Algebra Logic. 2000, 39 5 324-334

[87]

Moghaddamfar AR, Zokayi AR, Darafsheh MR. On the characterizability of the automorphism groups of sporadic simple groups by their element orders. Acta Math. Sin. (Engl. Ser.). 2004, 20 4 653-662

[88]

Praeger CE, Shi W. A characterization of some alternating and symmetric groups. Commun. Algebra. 1994, 22 5 1507-1530

[89]

Shao C, Jiang Q. A new characterization of $A_{22}$ by its spectrum. Comm. Algebra. 2010, 38 6 2138-2141

[90]

Shen R, Shi W, Zinov’eva MR. Recognition of simple groups $B_p(3)$ by the set of element orders. Siberian Math. J.. 2010, 51 2 244-254

[91]

Shi W. A characteristic property of ${PSL}_2(7)$. J. Aust. Math. Soc. Ser. A. 1984, 36 354-356

[92]

Shi W. A characteristic property of $A_5$. J. Southwest-China Teach. Univ.. 1986, 11 11-14(in Chinese)

[93]

Shi W. A characteristic property of $A_8$. Acta Math. Sinica (N. S.). 1987, 3 92-96

[94]

Shi W. A characterization of $J_1$ and $PSL_2(2^n)$. Adv. in Math. (Beijing). 1987, 16 397-401(in Chinese)

[95]

Shi W. A characteristic property of the Mathieu groups. Chin. Ann. Math. Ser. A. 1988, 9 5 575-580(in Chinese)

[96]

Shi W. On the simple $K_3$-groups. J. Southwest Teach. Univ. Ser. B. 1988, 13 3 1-4(in Chinese)

[97]

Shi, W.: A new characterization of the sporadic simple groups, in: Group theory (Singapore, 1987), pp. 531–540, de Gruyter, Berlin (1989)

[98]

Shi W. A characterization of the Conway simple group $Co_{2}$. J. Math. (Wuhan). 1989, 9 2 171-172in Chinese

[99]

Shi W. A characterization of the Higman-Sims simple group. Houston J. Math.. 1990, 16 4 597-602

[100]

Shi W. Using orders to characterize simple groups and related topics. Adv. in Math. (China). 1991, 20 2 135-141(in Chinese)

[101]

Shi W. A characterization of Suzuki’s simple groups. Proc. Am. Math. Soc.. 1992, 114 3 589-591

[102]

Shi W. The characterization of the sporadic simple groups by their element orders. Algebra Colloq.. 1994, 1 2 159-166

[103]

Shi W. Groups whose elements have given orders. Chin. Sci. Bull.. 1997, 42 21 1761-1764

[104]

Shi, W.: Arithmetical properties of finite groups, in: Groups St. Andrews 2005, vol. 2, pp. 646–653, London Math. Soc. Lecture Note Ser., 340, Cambridge Univ. Press, Cambridge (2007)

[105]

Shi, W.: On the order and the element orders of finite groups: results and problems. In: Ischia group theory 2010, pp. 313–333, World Sci. Publ., Hackensack, NJ (2012)

[106]

Shi W, Li H. A characterization of $M_{12}$ and $PSU(6,2)$. Acta Math. Sinica. 1989, 32 6 758-764(in Chinese)

[107]

Shi W, Tang C. A characterization of some orthogonal groups. Progr. Natur. Sci.. 1997, 7 2 155-162

[108]

Staroletov A. On almost recognizability by spectrum of simple classical groups. Int. J. Group Theory. 2017, 6 4 7-33

[109]

Staroletov AM. Unsolvability of finite groups isospectral to the alternating group of degree 10. Sib. Elektron. Mat. Izv.. 2008, 5 20-24

[110]

Staroletov AM. Groups isospectral to the degree 10 alternating group. Siberian Math. J.. 2010, 51 3 507-514

[111]

Staroletov AM. On recognition by spectrum of the simple groups $B_3(q)$, $C_3(q)$ and $D_4(q)$. Siberian Math. J.. 2012, 53 3 532-538

[112]

Staroletov AM. Composition factors of the finite groups isospectral to simple classical groups. Siberian Math. J.. 2021, 62 2 341-356

[113]

Suzuki M. On a class of doubly transitive groups. Ann. Math.. 1962, 75 105-145

[114]

Vasil’ev AV. On connection between the structure of a finite group and the properties of its prime graph. Siberian Math. J.. 2005, 46 3 396-404

[115]

Vasil’ev AV. On finite groups isospectral to simple classical groups. J. Algebra. 2015, 423 318-374

[116]

Vasil’ev AV, Gorshkov IB, Grechkoseeva MA, Kondrat’ev AS, Staroletov AM. On recognizability by spectrum of finite simple groups of types $B_n$, $C_n$, and $^2D_n$ for $n=2^k$. Proc. Steklov Inst. Math.. 2009, 267 suppl. 1 218-233

[117]

Vasil’ev AV, Grechkoseeva MA. Recognition by spectrum for finite simple linear groups of small dimensions over fields of characteristic $2$. Algebra Logic. 2008, 47 5 314-320

[118]

Vasil’ev AV, Grechkoseeva MA. Recognition by spectrum for simple classical groups in characteristic $2$. Siberian Math. J.. 2015, 56 6 1009-1018

[119]

Vasil’ev AV, Grechkoseeva MA, Mazurov VD. Characterization of the finite simple groups by spectrum and order. Algebra Logic. 2009, 48 6 385-409

[120]

Vasil’ev AV, Grechkoseeva MA, Mazurov VD. On finite groups isospectral to simple symplectic and orthogonal groups. Siberian Math. J.. 2009, 50 6 965-981

[121]

Vasil’ev AV, Grechkoseeva MA, Staroletov AM. On finite groups isospectral to simple linear and unitary groups. Siberian Math. J.. 2011, 52 1 30-40

[122]

Vasil’ev AV, Staroletov AM. Recognizability of $G_2(q)$ by spectrum. Algebra Logic. 2013, 52 1 1-14

[123]

Vasil’ev AV, Staroletov AM. Almost recognizability of simple exceptional groups of Lie type. Algebra Logic. 2015, 53 6 433-449

[124]

Vasil’ev AV, Vdovin EP. An adjacency criterion for the prime graph of a finite simple group. Algebra Logic. 2005, 44 6 381-406

[125]

Vasil’ev AV, Vdovin EP. Cocliques of maximal size in the prime graph of a finite simple group. Algebra Logic. 2011, 50 4 291-322

[126]

Williams JS. Prime graph components of finite groups. J. Algebra. 1981, 69 487-513

[127]

Xu M. Recognition of finite simple linear groups $L_4(2^k)$ by spectrum. Algebra Colloq.. 2010, 17 3 469-474

[128]

Yang N, Grechkoseeva MA, Vasil’ev AV. On the nilpotency of the solvable radical of a finite group isospectral to a simple group. J. Group Theory. 2020, 23 3 447-470

[129]

Yoshida, T.: On the Burnside rings of finite groups and finite categories. In: Commutative Algebra and Combinatorics (Kyoto, 1985), pp. 337–353, Adv. Stud. Pure Math., vol. 11, North-Holland, Amsterdam (1987)

[130]

Zavarnitsine AV. Recognition of alternating groups of degrees $r+1$ and $r+2$ for prime $r$ and the group of degree $16$ by the set of their element orders. Algebra Logic. 2000, 39 6 370-377

[131]

Zavarnitsine AV. Recognition of the simple groups $L_3(q)$ by element orders. J. Group Theory. 2004, 7 1 81-97

[132]

Zavarnitsine AV. The weights of irreducible ${SL}_3(q)$-modules in the defining characteristic. Siberian Math. J.. 2004, 45 2 261-268

[133]

Zavarnitsine AV. Recognition of the simple groups $U_3(q)$ by element orders. Algebra Logic. 2006, 45 2 106-116

[134]

Zavarnitsine AV. Exceptional action of the simple groups ${L}_4(q)$ in the defining characteristic. Sib. Elektron. Mat. Izv.. 2008, 5 68-74

[135]

Zavarnitsine AV. Properties of element orders in covers for $L_n(q)$ and $U_n(q)$. Siberian Math. J.. 2008, 49 2 246-256

[136]

Zavarnitsine AV. A solvable group isospectral to $S_4(3)$. Siberian Math. J.. 2010, 51 1 20-24

[137]

Zavarnitsine AV, Mazurov VD. Element orders in coverings of symmetric and alternating groups. Algebra Logic. 1999, 38 3 159-170

[138]

Zavarnitsine AV, Mazurov VD. On element orders in coverings of the simple groups $L_n(q)$ and $U_n(q)$. Proc. Steklov Inst. Math.. 2007, 257 suppl. 1 S145-S154

[139]

Zhurtov, A.Kh., Shermetova, M.Kh.: On groups isospectral to the automorphism group of the second sporadic Janko group. Sib. Elektron. Mat. Izv. 14, 1011–1016 (2017). (in Russian)

[140]

Zvezdina MA. Spectra of automorphic extensions of finite simple symplectic and orthogonal groups over fields of characteristic $2$. Sib. Elektron. Mat. Izv.. 2014, 11 823-832

[141]

Zvezdina MA. Spectra of automorphic extensions of finite simple exceptional groups of Lie type. Algebra Logic. 2016, 55 5 354-366

Funding

Government of Jiangsu Province(JSB2018014)

National Natural Science Foundation of China(12171126)

National Natural Science Foundation of China(11671063)

Российский Фонд Фундаментальных Исследований (РФФи)(20-51-00007)

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