Talk:Permutation group: Difference between revisions
imported>Boris Tsirelson (→Symmetry group: new section) |
imported>Boris Tsirelson (→More difficult?: new section) |
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Is the symmetry group always about affine transformations? In some context symmetries are motions (or isometries) rather than all affine transformations. More generally, isomorphisms of a given structure (of any kind) are often called symmetries. --[[User:Boris Tsirelson|Boris Tsirelson]] 07:18, 16 December 2010 (UTC) | Is the symmetry group always about affine transformations? In some context symmetries are motions (or isometries) rather than all affine transformations. More generally, isomorphisms of a given structure (of any kind) are often called symmetries. --[[User:Boris Tsirelson|Boris Tsirelson]] 07:18, 16 December 2010 (UTC) | ||
== English == | |||
I am not a native English speaker, but let me wonder, why "the set of permutations on a set of objects form a group, is called a permutation group" rather than "the set of permutations on a set of objects is a group, called a permutation group" or "permutations on a set of objects form a group, called a permutation group"? --[[User:Boris Tsirelson|Boris Tsirelson]] 07:20, 16 December 2010 (UTC) | |||
== More difficult? == | |||
"The existence of an identity is slightly more difficult to establish" — really? --[[User:Boris Tsirelson|Boris Tsirelson]] 07:23, 16 December 2010 (UTC) | |||
Latest revision as of 01:23, 16 December 2010
Symmetry group
Is the symmetry group always about affine transformations? In some context symmetries are motions (or isometries) rather than all affine transformations. More generally, isomorphisms of a given structure (of any kind) are often called symmetries. --Boris Tsirelson 07:18, 16 December 2010 (UTC)
English
I am not a native English speaker, but let me wonder, why "the set of permutations on a set of objects form a group, is called a permutation group" rather than "the set of permutations on a set of objects is a group, called a permutation group" or "permutations on a set of objects form a group, called a permutation group"? --Boris Tsirelson 07:20, 16 December 2010 (UTC)
More difficult?
"The existence of an identity is slightly more difficult to establish" — really? --Boris Tsirelson 07:23, 16 December 2010 (UTC)