static L minus(Collection a, O... b) {
Set set = asSet(b);
new L l;
for (O s : unnull(a))
if (!set.contains(s))
l.add(s);
ret l;
}
static BigInteger minus(BigInteger a, BigInteger b) {
ret a.subtract(b);
}
ifclass Complex
static Complex minus(Complex c) {
ret c == null ?: complex(-c.re(), -c.im());
}
endif
meta-for int also as double, long {
static int minus(int a, int b) {
ret a-b;
}
static int minus(int a) {
ret -a;
}
}