A cognitive signature™ encodes the exact structure of a graph.●It is a lossless encoding, similar to a Gödel numbering. *●For unlabeled graphs, integers are sufficient for a cognitive signature.●For example, 0 maps to and from an empty graph with no nodes or arcs.●1, 2, 3, 4, 5, and 6 can be mapped to and from the following graphs:●To encode the structure of conceptual graphs in Cognitive Memory, the cognitive signatures are based on generalized combinatorial maps. **By contrast, a word vector encodes labels, but not structure.●A word vector is a “bag of labels” that ignores the graph connections.●Word vectors are often used for measuring the similarity of documents.●But they discard the structural information necessary for reasoning, question answering, and language understanding.