| author | nipkow |
| Tue, 26 Nov 1996 14:28:17 +0100 | |
| changeset 2223 | 4b43a8d046e5 |
| permissions | -rw-r--r-- |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
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changeset
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(* Title: HOL/ex/Lagrange.thy |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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ID: $Id$ |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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Author: Tobias Nipkow |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
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Copyright 1996 TU Muenchen |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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This theory only contains a single thm, which is a lemma in Lagrange's proof |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
|
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that every natural number is the sum of 4 squares. It's sole purpose is to |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
|
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demonstrate ordered rewriting for commutative rings. |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
|
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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The enterprising reader might consider proving all of Lagrange's thm. |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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*) |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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Lagrange = Ring + |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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constdefs sq :: 'a::times => 'a |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
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"sq x == x*x" |
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
|
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4b43a8d046e5
A bit of commutative ing theory, with a simplification tacxtic and an example.
nipkow
parents:
diff
changeset
|
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end |