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(A can be mapped 1-1 into a proper subpart of itself)

Dedekind's formulation of infinite class

Who Cites Dedekind infinite?
Dedekind_infiniteDef  Dedekind-Infinite(A) == a:Af:(AA). Inj(AAf) & (x:Af(x) = a)
Thm*  A:Type. Dedekind-Infinite(A Prop
notDef  A == A  False
Thm*  A:Prop. (A Prop
injectDef  Inj(ABf) == a1,a2:Af(a1) = f(a2 B  a1 = a2
Thm*  A,B:Type, f:(AB). Inj(ABf Prop

Syntax:Dedekind-Infinite(A) has structure: Dedekind_infinite(A)

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