e / {8n+5} \

/ \

/ \

/ \

s b

/ \ / \

/ \ / \

ss sb bs bb

/ \ / \ / \ / \

sss ssb sbs sbb bss bsb bbs bbb

/ \ / \ / \ / \ / \ / \ / \ / \

Figure 4: First Three Levels of Abstract Predecessor Tree Using Symbolic Set Names