Deprecated: $wgMWOAuthSharedUserIDs=false is deprecated, set $wgMWOAuthSharedUserIDs=true, $wgMWOAuthSharedUserSource='local' instead [Called from MediaWiki\HookContainer\HookContainer::run in /var/www/html/w/includes/HookContainer/HookContainer.php at line 135] in /var/www/html/w/includes/Debug/MWDebug.php on line 372
On a splitting of the parallel postulate - MaRDI portal

On a splitting of the parallel postulate (Q2668175)

From MaRDI portal
scientific article
Language Label Description Also known as
English
On a splitting of the parallel postulate
scientific article

    Statements

    On a splitting of the parallel postulate (English)
    0 references
    3 March 2022
    0 references
    In the realm of Hilbert's absolute geometry \(\mathcal A\), the Euclidean parallel postulate \textbf{P} is known to be equivalent to the conjunction of the following two axioms: \begin{itemize} \item [\textbf{ML}] Given three parallel lines, there is a line that intersects all three of them. \item [\textbf{S}] Given a line \(a\) and a point \(P\) on \(a\), as well as two intersecting lines \(m\) and \(n\), both parallel to \(a\), there exists a line \(g\) through \(P\) which intersects \(m\) but not \(n\). \end{itemize} It is shown that the above equivalence breaks down once the order axioms or the congruence axioms of \(\mathcal A\) are weakened.
    0 references
    0 references
    parallel postulate
    0 references
    \textit{Lotschnittaxiom}
    0 references
    metric-Euclidean planes
    0 references
    ordered geometry
    0 references

    Identifiers