f
C
x1
x2
C
f
x1
f
x2
f
Z
Z
eqZList
C
x1
x2
C
y1
y2
and
eqZList
x1
y1
eqZList
x2
y2
eqZList
C
x1
x2
Z
False
eqZList
Z
C
y1
y2
False
eqZList
Z
Z
True
second
C
x1
x2
x2
first
C
x1
x2
x1
g
x
x
and
False
False
False
and
True
False
False
and
False
True
False
and
True
True
True
second
1
eqZList
2
Z
0
True
0
f
1
C
2
and
2
first
1
False
0
g
1
INNERMOST