1. A computer readable medium storing instructions which when executed by a computer, cause the computer to perform a method of determining a relationship between a first textual segment and textual information in a lexical knowledge base (LKB) having a plurality of interconnected logical graphs, each representative of a textual segment in a corpus, the method comprising: obtaining in an input logical form based on the first textual segment; matching the input logical form against the logical graphs in the LKB, identifying logical graphs as matching logical graphs even if the matching logical graphs differ from the input logical form lexically or structurally; and providing an output based on the matching logical graphs.