一句话:将准开放互模拟扩展到含 mismatch 的 π-演算,证明其与开放 barbed 互模拟一致,并有直觉主义模态逻辑刻画。
准开放互模拟是 π-演算中保证同余的最粗互模拟之一;将其扩展以处理 mismatch 守卫(不等式)并非显然,因为需要为名称不等提供构造性证据。本文提出准开放互模拟的最小扩展:允许制造新名以见证不等式,并证明该扩展具有典范性和稳健性,与开放 barbed 互模拟重合,且可由一种既有模态逻辑的直觉主义变体刻画。作者还分析更著名的开放互模拟,确定其处理 mismatch 的最粗扩展。文中给出隐私性质检查的应用,并使用证明助手 Abella 机器化验证示例与可靠性结果。
Quasi-open bisimilarity is the coarsest notion of bisimilarity for the π-calculus that is also a congruence. This work extends quasi-open bisimilarity to handle mismatch (guards with inequalities). This minimal extension of quasi-open bisimilarity allows fresh names to be manufactured to provide constructive evidence that an inequality holds. The extension of quasi-open bisimilarity is canonical and robust --- coinciding with open barbed bisimilarity (an objective notion of bisimilarity congruence) and characterised by an intuitionistic variant of an established modal logic. The more famous open bisimilarity is also considered, for which the coarsest extension for handling mismatch is identified. Applications to checking privacy properties are highlighted. Examples and soundness results are mechanised using the proof assistant Abella.