add method: LTL.check_vars
add method: LTL.check_vars
tulip-control/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control