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On quasi-Sasakian structure on a totally umbilical hypersurface of a six-dimensional Hermitian planar submanifold of Cayley algebra

DOI
10.5922/0321-4796-2022-53-1
Pages
5-12

Abstract

Six-dimensional planar submanifolds of Cayley algebra equipped with almost Hermitian structures induced by Brown — Gray three-fold vector cross products in  are considered.

We select the case when the almost Hermitian structures on such six-dimensional planar submanifolds of Cayley algebra are Hermitian, i. e. these structures are integrable. We study almost contact metric structures on totally umbilical hypersurfaces in such six-dimensional Hermitian pla­nar submanifolds of the octave algebra.

We prove that if these almost contact metric structures on a totally umbilical hypersurface of a six-dimensional Hermitian planar submani­fold of Cayley algebra are quasi-Sasakian, then they are Sasakian.

Reference

1. Gray, A.: Vector cross products on manifolds. Trans. Amer. Math. Soc., 141, 465—504 (1969).

2. Kirichenko, V. F.: Classification of Kählerian structures, defined by means of three-fold vector cross products on six-dimensional submani­folds of Cayley algebra. Izvestia Vuzov. Math., 8, 32—38 (1980).

3. Banaru, M. B., Kirichenko, V. F.: The Hermitian geometry of the
6-dimensional submanifolds of Cayley algebra. Russian Mathematical Sur­veys, 49:1, 223—225 (1994).

4. Banaru, M. B.: Geometry of 6-dimensional Hermitian manifolds of the octave algebra. J. Math. Sci. (New York). 207:3, 354—388 (2015).

5. Stepanova, L. V., Banaru, G. A., Banaru, M. B.: On geometry of QS-hy­persurfaces of Kählerian manifolds. Siberian Electronic Mathema­tical Reports, 15, 815—822 (2018).

6. Banaru, M. B., Banaru, G. A.: A note on six-dimensional planar Hermitian submanifolds of Cayley algebra. Bul. Acad. Ştiinţe a Repub. Moldova. Mat., 1:74, 23—32 (2014).

7. Banaru, M. B., Banaru, G. A.: 1-cosymplectic hypersurfaces axiom and six-dimensional planar Hermitian submanifolds of the Octonian. SUT J. Math., 51:1, 1—9 (2015).

8. Banaru, M. B., Banaru, G. A.: On planar 6-dimensional Hermitian submanifolds of Cayley algebra. DGMF. Kaliningrad. 48, 21—25 (2017).

9. Banaru, M. B., Banaru, G. A.: On stability of Hermitian structures on 6-dimensional planar submanifolds of Cayley algebra. DGMF. Kali­ningrad. 52, 23—29 (2021).

10. Kirichenko, V. F.: Differential-geometric structures on manifolds. Odessa (2013).

11. Kirichenko, V. F., Rustanov, A. R.: Differential geometry of quasi-Sasakian manifolds. Sb. Math., 193:8, 1173—1202 (2002).