Storage capacity of an associative memory model, HASP, is theoretically analyzed. Since HASP can resolve one-to-many associations by mutually inhibitory network, crosstalk noise appeared at the output of heteroassociative network will also be eliminated by the inhibitory network.
It is theoretically shown that when key and associative vectors are sparsely coded, the storage capacity of HASP is more than twice that of heteroassociative network. Since the number of connections of HASP is just twice that of heteroassociative network, its performance overwhelms that of heteroassociative network. It is also shown that the theoretical results are close to the results obtained by simulation studies.