diff options
Diffstat (limited to 'Sum.thy')
| -rw-r--r-- | Sum.thy | 22 |
1 files changed, 14 insertions, 8 deletions
@@ -57,10 +57,10 @@ overloading fst_nondep \<equiv> fst begin definition fst_dep :: "[Term, Typefam] \<Rightarrow> Term" where - "fst_dep A B \<equiv> indSum[A,B] (\<lambda>_. A) (\<lambda>x y. x)" + "fst_dep A B \<equiv> \<^bold>\<lambda>p: (\<Sum>x:A. B x). indSum[A,B] (\<lambda>_. A) (\<lambda>x y. x) p" definition fst_nondep :: "[Term, Term] \<Rightarrow> Term" where - "fst_nondep A B \<equiv> indSum[A, \<lambda>_. B] (\<lambda>_. A) (\<lambda>x y. x)" + "fst_nondep A B \<equiv> \<^bold>\<lambda>p: A \<times> B. indSum[A, \<lambda>_. B] (\<lambda>_. A) (\<lambda>x y. x) p" end overloading @@ -68,24 +68,30 @@ overloading snd_nondep \<equiv> snd begin definition snd_dep :: "[Term, Typefam] \<Rightarrow> Term" where - "snd_dep A B \<equiv> indSum[A,B] (\<lambda>p. B fst[A,B]`p) (\<lambda>x y. y)" + "snd_dep A B \<equiv> \<^bold>\<lambda>p: (\<Sum>x:A. B x). indSum[A,B] (\<lambda>p. B fst[A,B]`p) (\<lambda>x y. y) p" definition snd_nondep :: "[Term, Term] \<Rightarrow> Term" where - "snd_nondep A B \<equiv> indSum[A, \<lambda>_. B] (\<lambda>_. B) (\<lambda>x y. y)" + "snd_nondep A B \<equiv> \<^bold>\<lambda>p: A \<times> B. indSum[A, \<lambda>_. B] (\<lambda>_. B) (\<lambda>x y. y) p" end text "Properties of projections:" lemma fst_dep_comp: - assumes "a : A" and "b : B a" + assumes "B: A \<rightarrow> U" and "a : A" and "b : B a" shows "fst[A,B]`(a,b) \<equiv> a" -proof - - have "A : U" using assms(1) .. +proof (unfold fst_dep_def) (* GOOD AUTOMATION EXAMPLE *) + have "\<And>p. p : \<Sum>x:A. B x \<Longrightarrow> indSum[A, B] (\<lambda>_. A) (\<lambda>x y. x) p : A" .. + moreover have "(a, b) : \<Sum>x:A. B x" using assms .. + then have "fst[A,B]`(a,b) \<equiv> indSum[A, B] (\<lambda>_. A) (\<lambda>x y. x) (a,b)" unfolding fst_dep_def by (simp add: Prod_comp) + have "A : U" using assms(2) .. then have "\<lambda>_. A: \<Sum>x:A. B x \<rightarrow> U" . moreover have "\<And>x y. x : A \<Longrightarrow> (\<lambda>x y. x) x y : A" . - ultimately show "fst[A,B]`(a,b) \<equiv> a" unfolding fst_dep_def using assms by (rule Sum_comp) + moreover + ultimately show "fst[A,B]`(a,b) \<equiv> a" unfolding fst_dep_def using assms by simp qed +thm Sum_comp + lemma snd_dep_comp: assumes "a : A" and "b : B a" shows "snd[A,B]`(a,b) \<equiv> b" |