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Explicit translation of Kasparov cycles into GK^G level-one morphisms

Demonstrate an explicit translation showing that any Kasparov cycle z = [s_- ⊕ s_+, _- ⊕ _+, T] in KK^G(A,B) can be represented in GK^G as the level-one morphism t_+ ⋅ f_2 ⋅ f_1^{-1} ⋅ Δ_{t_-} ⋅ φ ⋅ e^{-1}, and, furthermore, determine that when the Hilbert modules underlying s_± are built from change of coefficient algebra, external tensor products, and direct sums, the corner embedding e in this translation is very special.

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Background

The paper develops GKG-theory as a generators-and-relations counterpart to KKG-theory and uses extended double splitexact sequences to describe level-one morphisms. It outlines how explicit formulas enable computation of products when actions are very special.

To extend these computations to KKG, the author proposes a conjectural translation that presents Kasparov cycles as GKG level-one morphisms with specified factors (t_+, f_2, f_1{-1}, Δ{t-}, φ, e{-1}). If the Hilbert modules in the cycle come from standard constructions (change of coefficients, external tensor products, direct sums), the translation is expected to use a very special corner embedding, enabling the explicit product computation framework to apply.

References

Conjecture [Translating $KKG$ to $GKG$] If $z=[s_- \oplus s_+, - \oplus _+,T]$ is a Kasparov cycle, then can be presented as $t+ f_2 f_1{-1} \Delta_{t_-} \varphi e{-1}$ in $GKG$-theory for $C*$-algebras as visualized in this diagram: ... If $_\pm$ are simple constructions as in table, then $e$ is a very special corner emebdding.

Computing the $K$-homology $K$-theory product in splitexact algebraic $KK$-theory (2508.03477 - Burgstaller, 5 Aug 2025) in Section 8 (Implications for KK-theory), Conjecture [Translating KK^G to GK^G]