While Jainism shared some features of Vedic Hinduism and Buddhism (such as asceticism for the sake of attaining liberation from rebirth), it also had a particular doctrine of its own.
For instance, Jainism taught that spirit (jīva) and matter (ajīva) were permanent but separate from each other.
The jīva in this case meant only the individual soul of a person, since the Jains did not believe in a universal spirit or God.
Therefore, there was nothing to correspond to brahman. And although ātman might be approximated to jīva, it had no permanent substantiality of its own.