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1. • CommentRowNumber1.
   • CommentAuthorPeter Heinig
   • CommentTimeJul 30th 2017
   • (edited Jul 30th 2017)
   • PermaLink
   Author: Peter Heinig
   Format: MarkdownItexTwo days ago, I created [[Ernst Steinitz]]. One reason was (I keep this notification short) something like I am working, for [[pasting schemes]], on *plane digraphs* -> working with embeddings becomes important -> a central theorem about plane graphs is of course Whitney's theorem about unique embeddability of 3-connected planar graphs -> arguably the most well-known, but heretofore not nLab-documented theorem about planar 3-connected graphs is [a theorem of Steinitz's](https://en.wikipedia.org/wiki/Steinitz%27s_theorem).

   Two days ago, I created

   Ernst Steinitz.

   One reason was (I keep this notification short) something like

   I am working, for pasting schemes, on plane digraphs -> working with embeddings becomes important -> a central theorem about plane graphs is of course Whitney’s theorem about unique embeddability of 3-connected planar graphs -> arguably the most well-known, but heretofore not nLab-documented theorem about planar 3-connected graphs is a theorem of Steinitz’s.

2. • CommentRowNumber2.
   • CommentAuthorjesse
   • CommentTimeJul 31st 2017
   • PermaLink
   Author: jesse
   Format: MarkdownItexThe exchange axiom for [[pregeometry|pregeometries]] is sometimes called the Steinitz exchange axiom (after its specialization to vector spaces, where it is sometimes known as the Steinitz exchange lemma.)

   The exchange axiom for pregeometries is sometimes called the Steinitz exchange axiom (after its specialization to vector spaces, where it is sometimes known as the Steinitz exchange lemma.)