src/HOL/Limits.thy
changeset 31353 14a58e2ca374
parent 31349 2261c8781f73
child 31355 3d18766ddc4b
equal deleted inserted replaced
31352:b3b534f06c2d 31353:14a58e2ca374
    18   show "(\<lambda>P. True) \<in> ?filter" by simp
    18   show "(\<lambda>P. True) \<in> ?filter" by simp
    19 qed
    19 qed
    20 
    20 
    21 definition
    21 definition
    22   eventually :: "('a \<Rightarrow> bool) \<Rightarrow> 'a filter \<Rightarrow> bool" where
    22   eventually :: "('a \<Rightarrow> bool) \<Rightarrow> 'a filter \<Rightarrow> bool" where
    23   "eventually P F \<longleftrightarrow> Rep_filter F P"
    23   [simp del]: "eventually P F \<longleftrightarrow> Rep_filter F P"
    24 
    24 
    25 lemma eventually_True [simp]: "eventually (\<lambda>x. True) F"
    25 lemma eventually_True [simp]: "eventually (\<lambda>x. True) F"
    26 unfolding eventually_def using Rep_filter [of F] by blast
    26 unfolding eventually_def using Rep_filter [of F] by blast
    27 
    27 
    28 lemma eventually_mono:
    28 lemma eventually_mono:
    83 
    83 
    84 subsection {* Convergence to Zero *}
    84 subsection {* Convergence to Zero *}
    85 
    85 
    86 definition
    86 definition
    87   Zfun :: "('a \<Rightarrow> 'b::real_normed_vector) \<Rightarrow> 'a filter \<Rightarrow> bool" where
    87   Zfun :: "('a \<Rightarrow> 'b::real_normed_vector) \<Rightarrow> 'a filter \<Rightarrow> bool" where
    88   "Zfun S F = (\<forall>r>0. eventually (\<lambda>i. norm (S i) < r) F)"
    88   [code del]: "Zfun S F = (\<forall>r>0. eventually (\<lambda>i. norm (S i) < r) F)"
    89 
    89 
    90 lemma ZfunI:
    90 lemma ZfunI:
    91   "(\<And>r. 0 < r \<Longrightarrow> eventually (\<lambda>i. norm (S i) < r) F) \<Longrightarrow> Zfun S F"
    91   "(\<And>r. 0 < r \<Longrightarrow> eventually (\<lambda>i. norm (S i) < r) F) \<Longrightarrow> Zfun S F"
    92 unfolding Zfun_def by simp
    92 unfolding Zfun_def by simp
    93 
    93 
   226 
   226 
   227 subsection{* Limits *}
   227 subsection{* Limits *}
   228 
   228 
   229 definition
   229 definition
   230   tendsto :: "('a \<Rightarrow> 'b::metric_space) \<Rightarrow> 'b \<Rightarrow> 'a filter \<Rightarrow> bool" where
   230   tendsto :: "('a \<Rightarrow> 'b::metric_space) \<Rightarrow> 'b \<Rightarrow> 'a filter \<Rightarrow> bool" where
   231   "tendsto f l net \<longleftrightarrow> (\<forall>e>0. eventually (\<lambda>x. dist (f x) l < e) net)"
   231   [code del]: "tendsto f l net \<longleftrightarrow> (\<forall>e>0. eventually (\<lambda>x. dist (f x) l < e) net)"
   232 
   232 
   233 lemma tendstoI:
   233 lemma tendstoI:
   234   "(\<And>e. 0 < e \<Longrightarrow> eventually (\<lambda>x. dist (f x) l < e) net)
   234   "(\<And>e. 0 < e \<Longrightarrow> eventually (\<lambda>x. dist (f x) l < e) net)
   235     \<Longrightarrow> tendsto f l net"
   235     \<Longrightarrow> tendsto f l net"
   236   unfolding tendsto_def by auto
   236   unfolding tendsto_def by auto