src/HOL/Topological_Spaces.thy
changeset 68296 69d680e94961
parent 68064 b249fab48c76
child 68361 20375f232f3b
equal deleted inserted replaced
68286:b9160ca067ae 68296:69d680e94961
  1922   "closed s \<Longrightarrow> closed t \<Longrightarrow> continuous_on s f \<Longrightarrow> continuous_on t g \<Longrightarrow>
  1922   "closed s \<Longrightarrow> closed t \<Longrightarrow> continuous_on s f \<Longrightarrow> continuous_on t g \<Longrightarrow>
  1923     \<forall>x. (x\<in>s \<and> \<not> P x) \<or> (x \<in> t \<and> P x) \<longrightarrow> f x = g x \<Longrightarrow>
  1923     \<forall>x. (x\<in>s \<and> \<not> P x) \<or> (x \<in> t \<and> P x) \<longrightarrow> f x = g x \<Longrightarrow>
  1924     continuous_on (s \<union> t) (\<lambda>x. if P x then f x else g x)"
  1924     continuous_on (s \<union> t) (\<lambda>x. if P x then f x else g x)"
  1925   by (rule continuous_on_If) auto
  1925   by (rule continuous_on_If) auto
  1926 
  1926 
  1927 lemma continuous_on_id[continuous_intros]: "continuous_on s (\<lambda>x. x)"
  1927 lemma continuous_on_id[continuous_intros,simp]: "continuous_on s (\<lambda>x. x)"
  1928   unfolding continuous_on_def by fast
  1928   unfolding continuous_on_def by fast
  1929 
  1929 
  1930 lemma continuous_on_id'[continuous_intros]: "continuous_on s id"
  1930 lemma continuous_on_id'[continuous_intros,simp]: "continuous_on s id"
  1931   unfolding continuous_on_def id_def by fast
  1931   unfolding continuous_on_def id_def by fast
  1932 
  1932 
  1933 lemma continuous_on_const[continuous_intros]: "continuous_on s (\<lambda>x. c)"
  1933 lemma continuous_on_const[continuous_intros,simp]: "continuous_on s (\<lambda>x. c)"
  1934   unfolding continuous_on_def by auto
  1934   unfolding continuous_on_def by auto
  1935 
  1935 
  1936 lemma continuous_on_subset: "continuous_on s f \<Longrightarrow> t \<subseteq> s \<Longrightarrow> continuous_on t f"
  1936 lemma continuous_on_subset: "continuous_on s f \<Longrightarrow> t \<subseteq> s \<Longrightarrow> continuous_on t f"
  1937   unfolding continuous_on_def
  1937   unfolding continuous_on_def
  1938   by (metis subset_eq tendsto_within_subset)
  1938   by (metis subset_eq tendsto_within_subset)