During March 2026, Antisubnoous enhanced the leanprover-community/mathlib4 repository by formalizing a theorem that expresses the Chebyshev theta function in terms of the prime counting function, deepening the analytic number theory framework. Working in Lean, they applied formal verification and theorem proving skills to create a clean, well-documented contribution that integrates with existing results, such as Chebyshev.primeCounting_eq_theta_div_log_add_integral. Their approach emphasized mathematical rigor and library stability, with automated checks ensuring CI readiness. Although no bugs were addressed during this period, the work provided a robust foundation for future proofs and reinforced the reliability of mathlib4’s number theory components.