A formal proof for the FSGNJ module has been created here: https://git.libre-riscv.org/?p=ieee754fpu.git;a=blob;f=src/ieee754/fsgnj/formal/proof_fsgnj_mod.py;h=b960a85c111c0caee39b99eded831d86b02903ad;hb=HEAD The proof can be run by the following command: python -m ieee754.fsgnj.formal.proof_fsgnj_mod