2493 fixes a :: "'a :: real_normed_vector" |
2493 fixes a :: "'a :: real_normed_vector" |
2494 shows "homeomorphism ((+) a ` S) S ((+) (- a)) ((+) a)" |
2494 shows "homeomorphism ((+) a ` S) S ((+) (- a)) ((+) a)" |
2495 unfolding homeomorphism_def by (auto simp: algebra_simps continuous_intros) |
2495 unfolding homeomorphism_def by (auto simp: algebra_simps continuous_intros) |
2496 |
2496 |
2497 lemma homeomorphism_ident: "homeomorphism T T (\<lambda>a. a) (\<lambda>a. a)" |
2497 lemma homeomorphism_ident: "homeomorphism T T (\<lambda>a. a) (\<lambda>a. a)" |
2498 by (rule homeomorphismI) (auto simp: continuous_on_id) |
2498 by (rule homeomorphismI) auto |
2499 |
2499 |
2500 lemma homeomorphism_compose: |
2500 lemma homeomorphism_compose: |
2501 assumes "homeomorphism S T f g" "homeomorphism T U h k" |
2501 assumes "homeomorphism S T f g" "homeomorphism T U h k" |
2502 shows "homeomorphism S U (h o f) (g o k)" |
2502 shows "homeomorphism S U (h o f) (g o k)" |
2503 using assms |
2503 using assms |
2504 unfolding homeomorphism_def |
2504 unfolding homeomorphism_def |
2505 by (intro conjI ballI continuous_on_compose) (auto simp: image_comp [symmetric]) |
2505 by (intro conjI ballI continuous_on_compose) (auto simp: image_iff) |
|
2506 |
2506 |
2507 |
2507 lemma homeomorphism_symD: "homeomorphism S t f g \<Longrightarrow> homeomorphism t S g f" |
2508 lemma homeomorphism_symD: "homeomorphism S t f g \<Longrightarrow> homeomorphism t S g f" |
2508 by (simp add: homeomorphism_def) |
2509 by (simp add: homeomorphism_def) |
2509 |
2510 |
2510 lemma homeomorphism_sym: "homeomorphism S t f g = homeomorphism t S g f" |
2511 lemma homeomorphism_sym: "homeomorphism S t f g = homeomorphism t S g f" |