src/HOL/Complex/ex/Sqrt.thy
changeset 21404 eb85850d3eb7
parent 19086 1b3780be6cc2
child 23413 5caa2710dd5b
equal deleted inserted replaced
21403:dd58f13a8eb4 21404:eb85850d3eb7
    16   The set of rational numbers, including the key representation
    16   The set of rational numbers, including the key representation
    17   theorem.
    17   theorem.
    18 *}
    18 *}
    19 
    19 
    20 definition
    20 definition
    21   rationals  ("\<rat>")
    21   rationals  ("\<rat>") where
    22   "\<rat> = {x. \<exists>m n. n \<noteq> 0 \<and> \<bar>x\<bar> = real (m::nat) / real (n::nat)}"
    22   "\<rat> = {x. \<exists>m n. n \<noteq> 0 \<and> \<bar>x\<bar> = real (m::nat) / real (n::nat)}"
    23 
    23 
    24 theorem rationals_rep [elim?]:
    24 theorem rationals_rep [elim?]:
    25   assumes "x \<in> \<rat>"
    25   assumes "x \<in> \<rat>"
    26   obtains m n where "n \<noteq> 0" and "\<bar>x\<bar> = real m / real n" and "gcd (m, n) = 1"
    26   obtains m n where "n \<noteq> 0" and "\<bar>x\<bar> = real m / real n" and "gcd (m, n) = 1"