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(* Title: HOLCF/coind.thy
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ID: $Id$
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Author: Franz Regensburger
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Copyright 1993 Technische Universitaet Muenchen
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Example for co-induction on streams
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*)
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Coind = Stream2 +
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consts
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nats :: "dnat stream"
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from :: "dnat -> dnat stream"
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rules
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nats_def "nats = fix[LAM h.scons[dzero][smap[dsucc][h]]]"
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from_def "from = fix[LAM h n.scons[n][h[dsucc[n]]]]"
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end
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(*
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smap[f][UU] = UU
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x~=UU --> smap[f][scons[x][xs]] = scons[f[x]][smap[f][xs]]
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nats = scons[dzero][smap[dsucc][nats]]
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from[n] = scons[n][from[dsucc[n]]]
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*)
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