doc-src/TutorialI/Sets/Relations.thy

Adapted to encoding of sets as predicates

(* ID:         $Id$ *)
theory Relations imports Main begin

ML "Pretty.setmargin 64"

(*Id is only used in UNITY*)
(*refl, antisym,trans,univalent,\<dots> ho hum*)

text{*
@{thm[display] Id_def[no_vars]}
\rulename{Id_def}
*}

text{*
@{thm[display] rel_comp_def[no_vars]}
\rulename{rel_comp_def}
*}

text{*
@{thm[display] R_O_Id[no_vars]}
\rulename{R_O_Id}
*}

text{*
@{thm[display] rel_comp_mono[no_vars]}
\rulename{rel_comp_mono}
*}

text{*
@{thm[display] converse_iff[no_vars]}
\rulename{converse_iff}
*}

text{*
@{thm[display] converse_rel_comp[no_vars]}
\rulename{converse_rel_comp}
*}

text{*
@{thm[display] Image_iff[no_vars]}
\rulename{Image_iff}
*}

text{*
@{thm[display] Image_UN[no_vars]}
\rulename{Image_UN}
*}

text{*
@{thm[display] Domain_iff[no_vars]}
\rulename{Domain_iff}
*}

text{*
@{thm[display] Range_iff[no_vars]}
\rulename{Range_iff}
*}

text{*
@{thm[display] relpow.simps[no_vars]}
\rulename{relpow.simps}

@{thm[display] rtrancl_refl[no_vars]}
\rulename{rtrancl_refl}

@{thm[display] r_into_rtrancl[no_vars]}
\rulename{r_into_rtrancl}

@{thm[display] rtrancl_trans[no_vars]}
\rulename{rtrancl_trans}

@{thm[display] rtrancl_induct[no_vars]}
\rulename{rtrancl_induct}

@{thm[display] rtrancl_idemp[no_vars]}
\rulename{rtrancl_idemp}

@{thm[display] r_into_trancl[no_vars]}
\rulename{r_into_trancl}

@{thm[display] trancl_trans[no_vars]}
\rulename{trancl_trans}

@{thm[display] trancl_into_rtrancl[no_vars]}
\rulename{trancl_into_rtrancl}

@{thm[display] trancl_converse[no_vars]}
\rulename{trancl_converse}
*}

text{*Relations.  transitive closure*}

lemma rtrancl_converseD: "(x,y) \<in> (r\<inverse>)\<^sup>* \<Longrightarrow> (y,x) \<in> r\<^sup>*"
apply (erule rtrancl_induct)
txt{*
@{subgoals[display,indent=0,margin=65]}
*};
 apply (rule rtrancl_refl)
apply (blast intro: rtrancl_trans)
done


lemma rtrancl_converseI: "(y,x) \<in> r\<^sup>* \<Longrightarrow> (x,y) \<in> (r\<inverse>)\<^sup>*"
apply (erule rtrancl_induct)
 apply (rule rtrancl_refl)
apply (blast intro: rtrancl_trans)
done

lemma rtrancl_converse: "(r\<inverse>)\<^sup>* = (r\<^sup>*)\<inverse>"
by (auto intro: rtrancl_converseI dest: rtrancl_converseD)

lemma rtrancl_converse: "(r\<inverse>)\<^sup>* = (r\<^sup>*)\<inverse>"
apply (intro equalityI subsetI)
txt{*
after intro rules

@{subgoals[display,indent=0,margin=65]}
*};
apply clarify
txt{*
after splitting
@{subgoals[display,indent=0,margin=65]}
*};
oops


lemma "(\<forall>u v. (u,v) \<in> A \<longrightarrow> u=v) \<Longrightarrow> A \<subseteq> Id"
apply (rule subsetI)
txt{*
@{subgoals[display,indent=0,margin=65]}

after subsetI
*};
apply clarify
txt{*
@{subgoals[display,indent=0,margin=65]}

subgoals after clarify
*};
by blast




text{*rejects*}

lemma "(a \<in> {z. P z} \<union> {y. Q y}) = P a \<or> Q a"
apply (blast)
done

text{*Pow, Inter too little used*}

lemma "(A \<subset> B) = (A \<subseteq> B \<and> A \<noteq> B)"
apply (simp add: psubset_eq)
done

end