src/HOL/Library/Extended_Real.thy
changeset 57025 e7fd64f82876
parent 56993 e5366291d6aa
child 57447 87429bdecad5
equal deleted inserted replaced
57024:c9e98c2498fd 57025:e7fd64f82876
  2166   }
  2166   }
  2167   then show ?thesis
  2167   then show ?thesis
  2168     by (auto simp: order_tendsto_iff)
  2168     by (auto simp: order_tendsto_iff)
  2169 qed
  2169 qed
  2170 
  2170 
       
  2171 lemma tendsto_PInfty_eq_at_top:
       
  2172   "((\<lambda>z. ereal (f z)) ---> \<infinity>) F \<longleftrightarrow> (LIM z F. f z :> at_top)"
       
  2173   unfolding tendsto_PInfty filterlim_at_top_dense by simp
       
  2174 
  2171 lemma tendsto_MInfty: "(f ---> -\<infinity>) F \<longleftrightarrow> (\<forall>r. eventually (\<lambda>x. f x < ereal r) F)"
  2175 lemma tendsto_MInfty: "(f ---> -\<infinity>) F \<longleftrightarrow> (\<forall>r. eventually (\<lambda>x. f x < ereal r) F)"
  2172   unfolding tendsto_def
  2176   unfolding tendsto_def
  2173 proof safe
  2177 proof safe
  2174   fix S :: "ereal set"
  2178   fix S :: "ereal set"
  2175   assume "open S" "-\<infinity> \<in> S"
  2179   assume "open S" "-\<infinity> \<in> S"