Dedekind 0.0.0
A structuralist C++23 Module Library
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dedekind::sequences::IsClassicallyConvergent Concept Referenceexport

A Cauchy sequence whose carrier sits in the classical logic regime, so the Cauchy ⇒ convergent collapse (limit extraction) fires honestly. More...

Concept definition

template<typename Seq>
std::same_as<convergence_logic<Seq>, dedekind::category::Boole>
A Seq is a Cauchy sequence: its tail is eventually arbitrarily small under the metric on the carrier.
Definition convergence.cppm:90
A Cauchy sequence whose carrier sits in the classical logic regime, so the Cauchy ⇒ convergent collap...
Definition convergence.cppm:160
The internal logic of the Classical Topos ({True, False}).
Definition logic.cppm:186

Detailed Description

A Cauchy sequence whose carrier sits in the classical logic regime, so the Cauchy ⇒ convergent collapse (limit extraction) fires honestly.

The LEM-flavoured step "every Cauchy sequence converges" is the completeness axiom; constructively it is blocked — Specker exhibits a computable Cauchy sequence of rationals whose limit is not computable. The carrier-axis cardinality cut (#622/#696) decides the regime via convergence_logic: a countable Codomain lands in Boole and the collapse fires; an uncountable carrier (the continuum, or a non-cardinality'd primitive like double — the float↔ℝ gap) lands in Kleene and the collapse is honestly rejected. The existence of the limit is then the classical theorem / the engineer's honesty obligation; this concept gates only the Cauchy shape and the regime, matching the project's concept-names-the-role discipline.

Form-chain row 7 of #719; the convergence half of the logical-collapse crown that WitnessesBolzanoWeierstrass completes.