equal
deleted
inserted
replaced
2078 with \<open>decseq X\<close> show "\<exists>L. X \<longlonglongrightarrow> L \<and> (\<forall>i. L \<le> X i)" |
2078 with \<open>decseq X\<close> show "\<exists>L. X \<longlonglongrightarrow> L \<and> (\<forall>i. L \<le> X i)" |
2079 by (auto intro!: exI[of _ L] decseq_le) |
2079 by (auto intro!: exI[of _ L] decseq_le) |
2080 qed |
2080 qed |
2081 |
2081 |
2082 |
2082 |
2083 subsubsection \<open>Cauchy Sequences are Bounded\<close> |
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2084 |
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2085 text \<open> |
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2086 A Cauchy sequence is bounded -- this is the standard |
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2087 proof mechanization rather than the nonstandard proof. |
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2088 \<close> |
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2089 |
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2090 lemma lemmaCauchy: "\<forall>n \<ge> M. norm (X M - X n) < (1::real) \<Longrightarrow> |
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2091 \<forall>n \<ge> M. norm (X n :: 'a::real_normed_vector) < 1 + norm (X M)" |
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2092 apply clarify |
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2093 apply (drule spec) |
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2094 apply (drule (1) mp) |
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2095 apply (simp only: norm_minus_commute) |
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2096 apply (drule order_le_less_trans [OF norm_triangle_ineq2]) |
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2097 apply simp |
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2098 done |
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2099 |
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2100 |
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2101 subsection \<open>Power Sequences\<close> |
2083 subsection \<open>Power Sequences\<close> |
2102 |
2084 |
2103 text \<open> |
2085 text \<open> |
2104 The sequence @{term "x^n"} tends to 0 if @{term "0\<le>x"} and @{term |
2086 The sequence @{term "x^n"} tends to 0 if @{term "0\<le>x"} and @{term |
2105 "x<1"}. Proof will use (NS) Cauchy equivalence for convergence and |
2087 "x<1"}. Proof will use (NS) Cauchy equivalence for convergence and |