If you iterate trough every concept RISC-V has, you might be able to prove it.

The RISC/MIPS concepts date back over 40 years. The base instruction set is intentionally designed with unencumbered, expired, or public-domain architectural concepts.

RICV-V microarchitectures and implementations are at much high risk of violating patents. Especially anything that is even slightly high performance. SiFive, Andes , and Alibaba’s T-Head are filing thousands of patents on microarchitectural optimizations and extensions. China's RISC-V patent-sharing alliances and other industry groups are building defensive patent cross-license around their RISC-V-related patents.