check_unknown     440 src/Monotonic.cpp     check_unknown(x == y);
check_unknown     441 src/Monotonic.cpp     check_unknown(x != y);
check_unknown     442 src/Monotonic.cpp     check_unknown(x*y);
check_unknown     452 src/Monotonic.cpp     check_unknown(select(x < 2, x, x-5));
check_unknown     453 src/Monotonic.cpp     check_unknown(select(x > 2, x-5, x));