Deferred Tax - DTA DTL liability, only, difference, regarding, valuation

Elliotbay

Just read on Elan notes that a DTL usually arises when an asset's tax base is lower than its carrying value.
But at the same time, the treatment of temporary difference says that when an asset tax base is greater that its carrying value, it reseults in a DTA.

Si I'm confused. What is the difference between the 2 ?

When do we have a DTL or a DTA from a liability or an asset exactly ?


Also, regarding the valuation allowance, is it applicable for both IFRS and USGaap or only USGaap ? Thanks