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6 *) |
6 *) |
7 |
7 |
8 header {* Completeness of the Reals; Floor and Ceiling Functions *} |
8 header {* Completeness of the Reals; Floor and Ceiling Functions *} |
9 |
9 |
10 theory RComplete |
10 theory RComplete |
11 imports Conditional_Complete_Lattices RealDef |
11 imports RealDef |
12 begin |
12 begin |
13 |
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14 lemma real_sum_of_halves: "x/2 + x/2 = (x::real)" |
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15 by simp |
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16 |
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17 lemma abs_diff_less_iff: |
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18 "(\<bar>x - a\<bar> < (r::'a::linordered_idom)) = (a - r < x \<and> x < a + r)" |
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19 by auto |
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20 |
13 |
21 subsection {* Completeness of Positive Reals *} |
14 subsection {* Completeness of Positive Reals *} |
22 |
15 |
23 text {* |
16 text {* |
24 \medskip Completeness properties using @{text "isUb"}, @{text "isLub"} etc. |
17 \medskip Completeness properties using @{text "isUb"}, @{text "isLub"} etc. |
25 *} |
18 *} |
26 |
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27 lemma real_isLub_unique: "[| isLub R S x; isLub R S y |] ==> x = (y::real)" |
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28 apply (frule isLub_isUb) |
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29 apply (frule_tac x = y in isLub_isUb) |
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30 apply (blast intro!: order_antisym dest!: isLub_le_isUb) |
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31 done |
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32 |
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33 |
19 |
34 text {* |
20 text {* |
35 \medskip reals Completeness (again!) |
21 \medskip reals Completeness (again!) |
36 *} |
22 *} |
37 |
23 |