
The work opens by asking a simple yet profound question: what does it mean for a collection of spatial changes to form a group? When any combination of allowed transformations stays within the set, it qualifies as a transformation group. Familiar examples—rigid motions, rotations about a point, and collineations—show how geometry can be viewed through such groups, while dualistic deformations only become groups when paired with collineations. Defining a “main group” that leaves all genuine geometric attributes untouched provides the basis for studying invariants.
From this foundation the book poses the central problem of modern geometry: given a manifold equipped with a chosen transformation group, examine the properties that remain unchanged under its actions. This leads to an invariant theory that works for any group, whether the full linear group or more exotic symmetries. The author stresses the freedom to select any transformation group, showing how classical, projective and newer approaches fit into a unified framework. Listeners are guided through the logical development without needing prior expertise in advanced algebra.
Language
de
Duration
~1 hours (81K characters)
Publisher of text edition
Project Gutenberg
Credits
Produced by R.S.
Release date
2011-11-16
Rights
Public domain in the USA.

1849–1925
A brilliant 19th-century mathematician, he helped reshape geometry by showing how different geometries could be understood through symmetry. His ideas, especially the famous Erlangen program, influenced generations of mathematicians and teachers.
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