Abstract
For a nonorientable closed surface standardly embedded in the –sphere, a diffeomorphism over this surface is extendable if and only if this diffeomorphism preserves the Guillou–Marin quadratic form of this embedded surface.
Citation
Susumu Hirose. "On diffeomorphisms over nonorientable surfaces standardly embedded in the $4$–sphere." Algebr. Geom. Topol. 12 (1) 109 - 130, 2012. https://doi.org/10.2140/agt.2012.12.109
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