src/HOL/Algebra/Sylow.thy
changeset 20318 0e0ea63fe768
parent 16663 13e9c402308b
child 25134 3d4953e88449
--- a/src/HOL/Algebra/Sylow.thy	Thu Aug 03 14:53:57 2006 +0200
+++ b/src/HOL/Algebra/Sylow.thy	Thu Aug 03 14:57:26 2006 +0200
@@ -3,9 +3,10 @@
     Author:     Florian Kammueller, with new proofs by L C Paulson
 *)
 
-header {* Sylow's theorem *}
+theory Sylow imports Coset begin
 
-theory Sylow imports Coset begin
+
+section {* Sylow's Theorem *}
 
 text {*
   See also \cite{Kammueller-Paulson:1999}.
@@ -50,9 +51,9 @@
 apply (blast elim!: quotientE)
 done
 
+
 subsection{*Main Part of the Proof*}
 
-
 locale sylow_central = sylow +
   fixes H and M1 and M
   assumes M_in_quot:  "M \<in> calM // RelM"
@@ -265,7 +266,7 @@
 done
 
 
-subsubsection{*The opposite injection*}
+subsubsection{*The Opposite Injection*}
 
 lemma (in sylow_central) H_elem_map:
      "H1 \<in> rcosets H ==> \<exists>g. g \<in> carrier G & H #> g = H1"
@@ -362,6 +363,9 @@
 lemma sylow_eq: "sylow G p a m = (group G & sylow_axioms G p a m)"
 by (simp add: sylow_def group_def)
 
+
+subsection {* Sylow's Theorem *}
+
 theorem sylow_thm:
      "[| prime p;  group(G);  order(G) = (p^a) * m; finite (carrier G)|]
       ==> \<exists>H. subgroup H G & card(H) = p^a"