src/HOL/SEQ.thy
changeset 37887 2ae085b07f2f
parent 37767 a2b7a20d6ea3
child 40811 ab0a8cc7976a
equal deleted inserted replaced
37886:2f9d3fc1a8ac 37887:2ae085b07f2f
   504       hence "\<exists>no. \<forall>n\<ge>no. \<bar>f n - lim f\<bar> < lim f - x"
   504       hence "\<exists>no. \<forall>n\<ge>no. \<bar>f n - lim f\<bar> < lim f - x"
   505         by (metis 0)
   505         by (metis 0)
   506       from this obtain no where "\<forall>n\<ge>no. \<bar>f n - lim f\<bar> < lim f - x"
   506       from this obtain no where "\<forall>n\<ge>no. \<bar>f n - lim f\<bar> < lim f - x"
   507         by blast
   507         by blast
   508       thus "lim f \<le> x"
   508       thus "lim f \<le> x"
   509         by (metis add_cancel_end add_minus_cancel diff_def linorder_linear 
   509         by (metis 1 LIMSEQ_le_const2 fn_le)
   510                   linorder_not_le minus_diff_eq abs_diff_less_iff fn_le) 
       
   511     qed
   510     qed
   512 qed
   511 qed
   513 
   512 
   514 text{* Given a binary function @{text "f:: nat \<Rightarrow> 'a \<Rightarrow> 'a"}, its values are uniquely determined by a function g *}
   513 text{* Given a binary function @{text "f:: nat \<Rightarrow> 'a \<Rightarrow> 'a"}, its values are uniquely determined by a function g *}
   515 
   514 
   969 apply (unfold Bseq_def, safe)
   968 apply (unfold Bseq_def, safe)
   970 apply (rule_tac [2] x = "k + norm x" in exI)
   969 apply (rule_tac [2] x = "k + norm x" in exI)
   971 apply (rule_tac x = K in exI, simp)
   970 apply (rule_tac x = K in exI, simp)
   972 apply (rule exI [where x = 0], auto)
   971 apply (rule exI [where x = 0], auto)
   973 apply (erule order_less_le_trans, simp)
   972 apply (erule order_less_le_trans, simp)
   974 apply (drule_tac x=n in spec, fold diff_def)
   973 apply (drule_tac x=n in spec, fold diff_minus)
   975 apply (drule order_trans [OF norm_triangle_ineq2])
   974 apply (drule order_trans [OF norm_triangle_ineq2])
   976 apply simp
   975 apply simp
   977 done
   976 done
   978 
   977 
   979 text{*alternative formulation for boundedness*}
   978 text{*alternative formulation for boundedness*}