src/HOL/Multivariate_Analysis/Topology_Euclidean_Space.thy
changeset 51472 adb441e4b9e9
parent 51471 cad22a3cc09c
child 51473 1210309fddab
equal deleted inserted replaced
51471:cad22a3cc09c 51472:adb441e4b9e9
  1414 
  1414 
  1415 lemma Lim_within_empty: "(f ---> l) (net within {})"
  1415 lemma Lim_within_empty: "(f ---> l) (net within {})"
  1416   unfolding tendsto_def Limits.eventually_within by simp
  1416   unfolding tendsto_def Limits.eventually_within by simp
  1417 
  1417 
  1418 lemma Lim_within_subset: "(f ---> l) (net within S) \<Longrightarrow> T \<subseteq> S \<Longrightarrow> (f ---> l) (net within T)"
  1418 lemma Lim_within_subset: "(f ---> l) (net within S) \<Longrightarrow> T \<subseteq> S \<Longrightarrow> (f ---> l) (net within T)"
  1419   unfolding tendsto_def Limits.eventually_within
  1419   unfolding tendsto_def Topological_Spaces.eventually_within
  1420   by (auto elim!: eventually_elim1)
  1420   by (auto elim!: eventually_elim1)
  1421 
  1421 
  1422 lemma Lim_Un: assumes "(f ---> l) (net within S)" "(f ---> l) (net within T)"
  1422 lemma Lim_Un: assumes "(f ---> l) (net within S)" "(f ---> l) (net within T)"
  1423   shows "(f ---> l) (net within (S \<union> T))"
  1423   shows "(f ---> l) (net within (S \<union> T))"
  1424   using assms unfolding tendsto_def Limits.eventually_within
  1424   using assms unfolding tendsto_def Limits.eventually_within
  4665     using `open U` and `f x \<in> U`
  4665     using `open U` and `f x \<in> U`
  4666     unfolding tendsto_def by fast
  4666     unfolding tendsto_def by fast
  4667   hence "eventually (\<lambda>y. f y \<noteq> a) (at x within s)"
  4667   hence "eventually (\<lambda>y. f y \<noteq> a) (at x within s)"
  4668     using `a \<notin> U` by (fast elim: eventually_mono [rotated])
  4668     using `a \<notin> U` by (fast elim: eventually_mono [rotated])
  4669   thus ?thesis
  4669   thus ?thesis
  4670     unfolding Limits.eventually_within Limits.eventually_at
  4670     unfolding Limits.eventually_within Metric_Spaces.eventually_at
  4671     by (rule ex_forward, cut_tac `f x \<noteq> a`, auto simp: dist_commute)
  4671     by (rule ex_forward, cut_tac `f x \<noteq> a`, auto simp: dist_commute)
  4672 qed
  4672 qed
  4673 
  4673 
  4674 lemma continuous_at_avoid:
  4674 lemma continuous_at_avoid:
  4675   fixes f :: "'a::metric_space \<Rightarrow> 'b::t1_space"
  4675   fixes f :: "'a::metric_space \<Rightarrow> 'b::t1_space"