src/HOL/Hyperreal/HyperNat.thy
changeset 20695 1cc6fefbff1a
parent 20552 2c31dd358c21
child 20730 da903f59e9ba
equal deleted inserted replaced
20694:76c49548d14c 20695:1cc6fefbff1a
   155 
   155 
   156 text{*Existence of infinite number not corresponding to any natural number
   156 text{*Existence of infinite number not corresponding to any natural number
   157 follows because member @{term FreeUltrafilterNat} is not finite.
   157 follows because member @{term FreeUltrafilterNat} is not finite.
   158 See @{text HyperDef.thy} for similar argument.*}
   158 See @{text HyperDef.thy} for similar argument.*}
   159 
   159 
       
   160 text{* Example of an hypersequence (i.e. an extended standard sequence)
       
   161    whose term with an hypernatural suffix is an infinitesimal i.e.
       
   162    the whn'nth term of the hypersequence is a member of Infinitesimal*}
       
   163 
       
   164 lemma SEQ_Infinitesimal:
       
   165       "( *f* (%n::nat. inverse(real(Suc n)))) whn : Infinitesimal"
       
   166 apply (simp add: hypnat_omega_def starfun star_n_inverse)
       
   167 apply (simp add: Infinitesimal_FreeUltrafilterNat_iff)
       
   168 apply (simp add: real_of_nat_Suc_gt_zero FreeUltrafilterNat_inverse_real_of_posnat)
       
   169 done
   160 
   170 
   161 lemma lemma_unbounded_set [simp]: "{n::nat. m < n} \<in> FreeUltrafilterNat"
   171 lemma lemma_unbounded_set [simp]: "{n::nat. m < n} \<in> FreeUltrafilterNat"
   162 apply (insert finite_atMost [of m]) 
   172 apply (insert finite_atMost [of m]) 
   163 apply (simp add: atMost_def) 
   173 apply (simp add: atMost_def) 
   164 apply (drule FreeUltrafilterNat_finite) 
   174 apply (drule FreeUltrafilterNat_finite)