src/HOL/Library/Extended_Real.thy
changeset 61585 a9599d3d7610
parent 61245 b77bf45efe21
child 61610 4f54d2759a0b
equal deleted inserted replaced
61584:f06e5a5a4b46 61585:a9599d3d7610
    12 begin
    12 begin
    13 
    13 
    14 text \<open>
    14 text \<open>
    15 
    15 
    16 This should be part of @{theory Extended_Nat} or @{theory Order_Continuity}, but then the
    16 This should be part of @{theory Extended_Nat} or @{theory Order_Continuity}, but then the
    17 AFP-entry @{text "Jinja_Thread"} fails, as it does overload certain named from @{theory Complex_Main}.
    17 AFP-entry \<open>Jinja_Thread\<close> fails, as it does overload certain named from @{theory Complex_Main}.
    18 
    18 
    19 \<close>
    19 \<close>
    20 
    20 
    21 lemma continuous_at_left_imp_sup_continuous:
    21 lemma continuous_at_left_imp_sup_continuous:
    22   fixes f :: "'a \<Rightarrow> 'a::{complete_linorder, linorder_topology}"
    22   fixes f :: "'a \<Rightarrow> 'a::{complete_linorder, linorder_topology}"
  3611 lemma inverse_ereal_tendsto_pos: 
  3611 lemma inverse_ereal_tendsto_pos: 
  3612   fixes x :: ereal assumes "0 < x"
  3612   fixes x :: ereal assumes "0 < x"
  3613   shows "inverse -- x --> inverse x"
  3613   shows "inverse -- x --> inverse x"
  3614 proof (cases x)
  3614 proof (cases x)
  3615   case (real r)
  3615   case (real r)
  3616   with `0 < x` have **: "(\<lambda>x. ereal (inverse x)) -- r --> ereal (inverse r)"
  3616   with \<open>0 < x\<close> have **: "(\<lambda>x. ereal (inverse x)) -- r --> ereal (inverse r)"
  3617     by (auto intro!: tendsto_inverse)
  3617     by (auto intro!: tendsto_inverse)
  3618   from real \<open>0 < x\<close> show ?thesis
  3618   from real \<open>0 < x\<close> show ?thesis
  3619     by (auto simp: at_ereal tendsto_compose_filtermap[symmetric] eventually_at_filter
  3619     by (auto simp: at_ereal tendsto_compose_filtermap[symmetric] eventually_at_filter
  3620              intro!: Lim_transform_eventually[OF _ **] t1_space_nhds)
  3620              intro!: Lim_transform_eventually[OF _ **] t1_space_nhds)
  3621 qed (insert \<open>0 < x\<close>, auto intro!: inverse_infty_ereal_tendsto_0)
  3621 qed (insert \<open>0 < x\<close>, auto intro!: inverse_infty_ereal_tendsto_0)