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advanced_tools:group_theory [2018/03/28 16:23]
jakobadmin [Intuitive]
advanced_tools:group_theory [2018/03/28 16:25]
jakobadmin [Abstract]
Line 142: Line 142:
  
 <tabbox Abstract> ​ <tabbox Abstract> ​
-<​blockquote>​The case I have chosen to treat in this paper concerns the question as to whether 
-the group concept should be extended to, or even subsumed by, the [[advanced_tools:​category_theory:​groupoids|groupoid concept]]. 
-Over a period stretching from at least as long ago as the early nineteenth 
-century, the group concept has emerged as the standard way to measure the degree 
-of invariance of an object under some collection of transformations.4 The informal 
-ideas codified by the group axioms, an axiomatisation which even Lakatos thought 
-unlikely to be challenged, relate to the composition of reversible processes 
-revealing the symmetry of a mathematical entity. Two early manifestations of 
-groups were as the permutations of the roots of a polynomial, later re-interpreted 
-as the automorphisms of the algebraic number field containing its roots, in Galois 
-theory, and as the structure-preserving automorphisms of a geometric space in the 
-Erlanger Programme. Intriguingly,​ it now appears that there is a challenger on the 
-scene. In some situations, it is argued, groupoids are better suited to extracting the 
-vital symmetries. And yet there has been a perception among their supporters— 
-who include some very illustrious names—of an unwarranted resistance in some 
-quarters to their use, which is only now beginning to decline.<​cite>​[[http://​www.sciencedirect.com/​science/​article/​pii/​S0039368101000073|The importance of mathematical conceptualisation]] by David Corfield</​cite></​blockquote>​ 
- 
- 
   * One of the best books to get familiar with many of the most important advanced topics in group theory is "​Geometrical methods of mathematical physics"​ by Bernard F. Schutz   * One of the best books to get familiar with many of the most important advanced topics in group theory is "​Geometrical methods of mathematical physics"​ by Bernard F. Schutz
   * Other nice advanced textbooks are:   * Other nice advanced textbooks are:
Line 170: Line 152:
     * J. Frank Adams, Lectures on Lie Groups     * J. Frank Adams, Lectures on Lie Groups
  
- <​blockquote>​ +----
-Consider two descriptions of the same phenomenon: (1) Space is homogeneousand isotropic. (2) Space is invariant under translations and rotations of coor-dinates. Statements in the logical form of (1) were exclusive in pre-twentiethcentury physics. Statements in the form -of (2) dominate twentieth centuryphysics;​ quantum mechanics contains various representations of the same phy-sical state and rules for transforming among them. Description (1) appearsclean;​ it describes nature without explicit conventional and experientialnotions. Description (2) is all contaminated;​ it invokes conventional coordi-nates and intellectual transformations of the coordinates. The coordinates areusually interpreted as perspectives of observations;​ so they are somehowrelated to human subjects. However, physicists agree that (2) is more objective,​for it uncovers the hidden presuppositions of (1) and neutralizes their undesir-able effects. They retrofit the conceptual structure embodied in (2) into classi-cal mechanics to make it more satisfactory. The statement (1) is often interpreted in a framework of things; (2) can beinterpreted in the framework of objects. The object framework includes thething framework as a substructure and further conveys the epistemological ideathat the things are knowable through observations and yet independent ofobservations. The two frameworks exemplify two different views of the world +
-<​cite>​From "How is Quantum Field Theory possible"​ by Auyang</​cite>​ +
-</​blockquote>​+
  
  
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   * [[advanced_tools:​group_theory:​group_contraction]]   * [[advanced_tools:​group_theory:​group_contraction]]
  
 +<tabbox Research>​
  
 +<​blockquote>​The case I have chosen to treat in this paper concerns the question as to whether
 +the group concept should be extended to, or even subsumed by, the [[advanced_tools:​category_theory:​groupoids|groupoid concept]].
 +Over a period stretching from at least as long ago as the early nineteenth
 +century, the group concept has emerged as the standard way to measure the degree
 +of invariance of an object under some collection of transformations.4 The informal
 +ideas codified by the group axioms, an axiomatisation which even Lakatos thought
 +unlikely to be challenged, relate to the composition of reversible processes
 +revealing the symmetry of a mathematical entity. Two early manifestations of
 +groups were as the permutations of the roots of a polynomial, later re-interpreted
 +as the automorphisms of the algebraic number field containing its roots, in Galois
 +theory, and as the structure-preserving automorphisms of a geometric space in the
 +Erlanger Programme. Intriguingly,​ it now appears that there is a challenger on the
 +scene. In some situations, it is argued, groupoids are better suited to extracting the
 +vital symmetries. And yet there has been a perception among their supporters—
 +who include some very illustrious names—of an unwarranted resistance in some
 +quarters to their use, which is only now beginning to decline.<​cite>​[[http://​www.sciencedirect.com/​science/​article/​pii/​S0039368101000073|The importance of mathematical conceptualisation]] by David Corfield</​cite></​blockquote>​
    
 <tabbox FAQ> ​ <tabbox FAQ> ​
advanced_tools/group_theory.txt · Last modified: 2020/09/07 05:18 by 14.161.7.200