Matches in SemOpenAlex for { <https://semopenalex.org/work/W1955254446> ?p ?o ?g. }
- W1955254446 endingPage "109" @default.
- W1955254446 startingPage "87" @default.
- W1955254446 abstract "A space-like surface S immersed in a 4-dimensional Lorentzian manifold will be said to be umbilical along a direction N normal to S if the second fundamental form along N is proportional to the first fundamental form of S. In particular, S is pseudo-umbilical if it is umbilical along the mean curvature vector field H and (totally) umbilical if it is umbilical along all possible normal directions. The possibility that the surface be umbilical along the unique normal direction orthogonal to H—“ortho-umbilical” surface—is also considered. I prove that the necessary and sufficient condition for S to be umbilical along a normal direction is that two independent Weingarten operators (and, a fortiori, all of them) commute, or equivalently that the shape tensor be diagonalizable on S. The umbilical direction is then uniquely determined. This can be seen to be equivalent to a condition relating the normal curvature and the appropriate part of the Riemann tensor of the space time. In particular, for conformally flat space-times (including Lorentz space forms) the necessary and sufficient condition is that the normal curvature vanishes. Some further consequences are analyzed, and the extension of the main results to arbitrary signatures and higher dimensions is briefly discussed." @default.
- W1955254446 created "2016-06-24" @default.
- W1955254446 creator A5091729448 @default.
- W1955254446 date "2012-01-01" @default.
- W1955254446 modified "2023-09-24" @default.
- W1955254446 title "Umbilical-Type Surfaces in SpaceTime" @default.
- W1955254446 cites W1511953149 @default.
- W1955254446 cites W1855915878 @default.
- W1955254446 cites W1953478438 @default.
- W1955254446 cites W1963863559 @default.
- W1955254446 cites W1966845790 @default.
- W1955254446 cites W1967532183 @default.
- W1955254446 cites W1974894190 @default.
- W1955254446 cites W1976957611 @default.
- W1955254446 cites W1980851479 @default.
- W1955254446 cites W1987167442 @default.
- W1955254446 cites W1990189167 @default.
- W1955254446 cites W2012618762 @default.
- W1955254446 cites W2018378689 @default.
- W1955254446 cites W2025205452 @default.
- W1955254446 cites W2029403139 @default.
- W1955254446 cites W2042317870 @default.
- W1955254446 cites W2052045615 @default.
- W1955254446 cites W2059625841 @default.
- W1955254446 cites W2068455781 @default.
- W1955254446 cites W2072456967 @default.
- W1955254446 cites W3038111750 @default.
- W1955254446 cites W3101652471 @default.
- W1955254446 cites W3102836082 @default.
- W1955254446 cites W3104416779 @default.
- W1955254446 cites W3104471943 @default.
- W1955254446 cites W3122389990 @default.
- W1955254446 cites W3123115191 @default.
- W1955254446 cites W4214777000 @default.
- W1955254446 cites W4233907720 @default.
- W1955254446 cites W4234022209 @default.
- W1955254446 cites W4234933822 @default.
- W1955254446 cites W4312960833 @default.
- W1955254446 cites W3123915040 @default.
- W1955254446 doi "https://doi.org/10.1007/978-1-4614-4897-6_3" @default.
- W1955254446 hasPublicationYear "2012" @default.
- W1955254446 type Work @default.
- W1955254446 sameAs 1955254446 @default.
- W1955254446 citedByCount "3" @default.
- W1955254446 countsByYear W19552544462016 @default.
- W1955254446 countsByYear W19552544462017 @default.
- W1955254446 crossrefType "book-chapter" @default.
- W1955254446 hasAuthorship W1955254446A5091729448 @default.
- W1955254446 hasBestOaLocation W19552544462 @default.
- W1955254446 hasConcept C111919701 @default.
- W1955254446 hasConcept C118732077 @default.
- W1955254446 hasConcept C121332964 @default.
- W1955254446 hasConcept C127413603 @default.
- W1955254446 hasConcept C130187892 @default.
- W1955254446 hasConcept C134306372 @default.
- W1955254446 hasConcept C155281189 @default.
- W1955254446 hasConcept C183517385 @default.
- W1955254446 hasConcept C18903297 @default.
- W1955254446 hasConcept C195065555 @default.
- W1955254446 hasConcept C198959055 @default.
- W1955254446 hasConcept C202444582 @default.
- W1955254446 hasConcept C2524010 @default.
- W1955254446 hasConcept C2776799497 @default.
- W1955254446 hasConcept C2777299769 @default.
- W1955254446 hasConcept C2778572836 @default.
- W1955254446 hasConcept C33923547 @default.
- W1955254446 hasConcept C41008148 @default.
- W1955254446 hasConcept C529865628 @default.
- W1955254446 hasConcept C5667645 @default.
- W1955254446 hasConcept C62520636 @default.
- W1955254446 hasConcept C74650414 @default.
- W1955254446 hasConcept C78519656 @default.
- W1955254446 hasConcept C86803240 @default.
- W1955254446 hasConceptScore W1955254446C111919701 @default.
- W1955254446 hasConceptScore W1955254446C118732077 @default.
- W1955254446 hasConceptScore W1955254446C121332964 @default.
- W1955254446 hasConceptScore W1955254446C127413603 @default.
- W1955254446 hasConceptScore W1955254446C130187892 @default.
- W1955254446 hasConceptScore W1955254446C134306372 @default.
- W1955254446 hasConceptScore W1955254446C155281189 @default.
- W1955254446 hasConceptScore W1955254446C183517385 @default.
- W1955254446 hasConceptScore W1955254446C18903297 @default.
- W1955254446 hasConceptScore W1955254446C195065555 @default.
- W1955254446 hasConceptScore W1955254446C198959055 @default.
- W1955254446 hasConceptScore W1955254446C202444582 @default.
- W1955254446 hasConceptScore W1955254446C2524010 @default.
- W1955254446 hasConceptScore W1955254446C2776799497 @default.
- W1955254446 hasConceptScore W1955254446C2777299769 @default.
- W1955254446 hasConceptScore W1955254446C2778572836 @default.
- W1955254446 hasConceptScore W1955254446C33923547 @default.
- W1955254446 hasConceptScore W1955254446C41008148 @default.
- W1955254446 hasConceptScore W1955254446C529865628 @default.
- W1955254446 hasConceptScore W1955254446C5667645 @default.
- W1955254446 hasConceptScore W1955254446C62520636 @default.
- W1955254446 hasConceptScore W1955254446C74650414 @default.
- W1955254446 hasConceptScore W1955254446C78519656 @default.
- W1955254446 hasConceptScore W1955254446C86803240 @default.
- W1955254446 hasLocation W19552544461 @default.