In several applications of logic programming and Transaction Logic, such as, planning, trust management and independent Semantic Web Services, an action might produce incomplete facts and leave existential values in an incrementally generated data structure. The same action or other producer or consumer actions might read, modify or communicate through these facts, making this technique a powerful communication technique. In this poster, we present a definite semantics for these existentially quantified values that occur only in facts, queries and updates of facts. Although this simple semantics applies only to facts and not to clauses, it is relevant to many applications, including artificial intelligence planning, workflow modeling and verification, and updates of facts in the Semantic Web. Sequential Transaction Logic and Existential Values in Queries and Updates of Facts This poster reports on the study of existential quantified values in updates of facts for the Transaction Logic...