John F. Sowa's Conceptual Graphs allow the graphical statement of logic propositions, or predicates. Like the Unified Modeling Language, they allow construction of statements such as

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Sowa credits the Existential Graphs of Charles Sanders Peirce for his conceptual graphs. See also conceptual schema, semantic network, knowledge representation. Together with concepts like principal components analysis, Tuevo Kohonen's self-organizing map and Bayesian inference, Sowa's conceptual graphs may eventually make it possible to implement agentss for unsupervised learning.

Reference: John F. Sowa, Conceptual Structures 1984 IBM Systems Programming Series ISBN 0-201-14472-7