Elias Tazartes developed no_std HashMap support for the cairo-air module in the starkware-libs/stwo-cairo repository, enabling the prover to operate in environments without the Rust standard library. He refactored multiple modules to replace the standard HashMap with a no_std-compatible alternative, addressing portability and deployment constraints for toolchains with limited resources. This work required careful cross-module changes to maintain code integrity and ensure maintainability. Using Rust and leveraging expertise in Cairo and no standard library development, Elias delivered a focused feature that reduces dependency risks and broadens the deployment options for stwo-cairo, demonstrating depth in low-level systems engineering.