src/HOL/Algebra/abstract/RingHomo.thy
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(*
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    Ring homomorphism
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    $Id$
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    Author: Clemens Ballarin, started 15 April 1997
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*)
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RingHomo = NatSum +
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consts
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  homo	:: ('a::ringS => 'b::ringS) => bool
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defs
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  homo_def	"homo f == (ALL a b. f (a + b) = f a + f b &
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			      f (a * b) = f a * f b) &
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			   f <1> = <1>"
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end