src/HOL/Topological_Spaces.thy
changeset 61806 d2e62ae01cd8
parent 61799 4cf66f21b764
child 61810 3c5040d5694a
equal deleted inserted replaced
61799:4cf66f21b764 61806:d2e62ae01cd8
  1756     by (rule compactE)
  1756     by (rule compactE)
  1757   from \<open>D \<subseteq> ?C\<close> have "\<forall>x\<in>D. eventually (\<lambda>y. y \<notin> x) (nhds y)" by auto
  1757   from \<open>D \<subseteq> ?C\<close> have "\<forall>x\<in>D. eventually (\<lambda>y. y \<notin> x) (nhds y)" by auto
  1758   with \<open>finite D\<close> have "eventually (\<lambda>y. y \<notin> \<Union>D) (nhds y)"
  1758   with \<open>finite D\<close> have "eventually (\<lambda>y. y \<notin> \<Union>D) (nhds y)"
  1759     by (simp add: eventually_ball_finite)
  1759     by (simp add: eventually_ball_finite)
  1760   with \<open>s \<subseteq> \<Union>D\<close> have "eventually (\<lambda>y. y \<notin> s) (nhds y)"
  1760   with \<open>s \<subseteq> \<Union>D\<close> have "eventually (\<lambda>y. y \<notin> s) (nhds y)"
  1761     by (auto elim!: eventually_mono [rotated])
  1761     by (auto elim!: eventually_mono')
  1762   thus "\<exists>t. open t \<and> y \<in> t \<and> t \<subseteq> - s"
  1762   thus "\<exists>t. open t \<and> y \<in> t \<and> t \<subseteq> - s"
  1763     by (simp add: eventually_nhds subset_eq)
  1763     by (simp add: eventually_nhds subset_eq)
  1764 qed
  1764 qed
  1765 
  1765 
  1766 lemma compact_continuous_image:
  1766 lemma compact_continuous_image: