We propose computational, declarative definitions of the concepts of weak and strong trust relations between interacting agents, and trust domains of trust-related agents in distributed systems. Our definitions yield computational complexity results for deciding potential and actual trust relationships and membership in trust domains, as well as a positive (negative) compositionality result for strong (weak) trust domains. Our defining principle for weak and strong trust is (common) belief in and knowledge of agent correctness, respectively.

KEYWORDS:

computability, compositionality, and scalability of trust and trustworthiness computer-aided decision making (CADM) dependable distributed or multi-agent systems modal logics of belief and knowledge.