Powered by OpenAIRE graph
Found an issue? Give us feedback
image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ Proceedings of the A...arrow_drop_down
image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
zbMATH Open
Article
Data sources: zbMATH Open
Proceedings of the American Mathematical Society
Article . 1957 . Peer-reviewed
Data sources: Crossref
Proceedings of the American Mathematical Society
Article . 1957 . Peer-reviewed
Data sources: Crossref
versions View all 3 versions
addClaim

This Research product is the result of merged Research products in OpenAIRE.

You have already added 0 works in your ORCID record related to the merged Research product.

Metrizations of Projective Spaces

Metrizations of projective spaces
Authors: Busemann, H.;

Metrizations of Projective Spaces

Abstract

A two-dimensional G-space,1 in which the geodesic through two distinct points is unique, is either homeomorphic to the plane E2 and all geodesics are isometric to a straight line, or it is homeomorphic to the projective plane p2 and all geodesics are isometric to the same circle, see [1, ??10 and 31]. Two problems arise in either case: (1) To determine the systems of curves (in E2 or p2) which occur as geodesics. (2) If the geodesics are (or lie on) ordinary straight lines, can the space be imbedded in a higher-dimensional space with the ordinary straight lines as geodesics? The author solved both these problems for E2, [1, Theorems (11.2) and (14.8)], but left both open for p2 [1, Appendix (9) and (10)]. Recently Skornyakov [2] solved the first problem for p2; he modified the author's basic idea through replacing a summation by an integration, and thus eliminated the singularities which the author's procedure would produce in the case of p2. The purpose of this note is to show that a device similar to Skornyakov's can be used to solve Problem (2) for pn. Our method also provides a much simpler solution of Problem (1). Thus we are going to prove simultaneously:

Keywords

metric geometry, convex geometry, integral geometry

  • BIP!
    Impact byBIP!
    selected citations
    These citations are derived from selected sources.
    This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
    3
    popularity
    This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
    Average
    influence
    This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
    Average
    impulse
    This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
    Average
Powered by OpenAIRE graph
Found an issue? Give us feedback
selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
3
Average
Average
Average
bronze