Figure 8.

Example of dual encoding. An example of read is represented in the dual alphabet. The symbols ${\downarrow }_{/j}^{-}$ (j ≥ 1) represent a mismatch against the − sequence, the symbols ${\downarrow }_{/j}^{+}$ (j ≥ 1) represent a mismatch against the + sequence, and the symbol ⇓ represents a mismatch against both. The index i is the match length of the sequence that is not mismatched. The symbolic + and − sequences are represented below, where an open square stands for a match and a closed square stands for a mismatch.