src/HOL/ex/Groebner_Examples.thy
changeset 25255 66ee31849d13
parent 23581 297c6d706322
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     4 *)
     4 *)
     5 
     5 
     6 header {* Groebner Basis Examples *}
     6 header {* Groebner Basis Examples *}
     7 
     7 
     8 theory Groebner_Examples
     8 theory Groebner_Examples
     9 imports Main
     9 imports Groebner_Basis
    10 begin
    10 begin
    11 
    11 
    12 subsection {* Basic examples *}
    12 subsection {* Basic examples *}
    13 
    13 
    14 lemma "3 ^ 3 == (?X::'a::{number_ring,recpower})"
    14 lemma "3 ^ 3 == (?X::'a::{number_ring,recpower})"
    96   shows "collinear (Ax * c - Ay * s, Ay * c + Ax * s)
    96   shows "collinear (Ax * c - Ay * s, Ay * c + Ax * s)
    97     (Bx * c - By * s, By * c + Bx * s) (Cx * c - Cy * s, Cy * c + Cx * s)"
    97     (Bx * c - By * s, By * c + Bx * s) (Cx * c - Cy * s, Cy * c + Cx * s)"
    98   using assms 
    98   using assms 
    99   by (algebra add: collinear_def split_def fst_conv snd_conv)
    99   by (algebra add: collinear_def split_def fst_conv snd_conv)
   100 
   100 
       
   101 lemma "EX (d::int). a*y - a*x = n*d \<Longrightarrow> EX u v. a*u + n*v = 1 \<Longrightarrow> EX e. y - x = n*e"
       
   102   apply algebra
       
   103   done
       
   104 
   101 end
   105 end