f tt x f eq x half double x s x eq s x s y eq x y eq 0 0 tt double s x s s double x double 0 0 half s s x s half x half 0 0 2.2 half s s x half x f tt x double x double s x double x f tt x half double x f tt x f eq x half double x s x eq s x s y eq x y f tt x eq x half double x true f tt x f eq x half double x s x true Failed! NaTT certifiable-1.6