Anticyclotomic Euler system over biquadratic fields
Kim Tuan Do
TL;DR
This work constructs a new anticyclotomic Euler system for the conjugate-self-dual Galois representation $V_{f,χ}$ attached to a weight-$k$ newform twisted by an anticyclotomic character over an imaginary biquadratic field. The construction begins with weight $(2,2,2)$ diagonal cycles and extends to general weights via Hida families, establishing tame and wild norm relations in the ring-class and anticyclotomic $\mathbf{Z}_p^2$-extensions. The authors derive reciprocity laws tying Euler-system classes to triple-product $p$-adic $L$-functions, and use the JNS framework to obtain Bloch–Kato results in rank $0$, along with divisibility toward the anticyclotomic Iwasawa main conjecture and consequences in rank $1$. These results extend the Heegner-point paradigm to a biquadratic CM setting, providing new evidence for deep conjectures in arithmetic of automorphic representations and Iwasawa theory, with explicit Selmer- and $L$-function connections.
Abstract
We construct a new Euler system (anticyclotomic, in the sense of Jetchev-Nekovar-Skinner) for the Galois representation $V_{f,χ}$ attached to a newform $f$ of weight $k\geq 2$ twisted by an anticyclotomic Hecke character $χ$ defined over an imaginary biquadratic field $K_0$. We then show some arithmetic applications of the constructed Euler system, including results on the Bloch-Kato conjecture and a divisibility towards the Iwasawa-Greenberg main conjecture for $V_{f,χ}$.
