The AMT is a separate, parallel federal income tax system with its own rates and rules; for example, the AMT effectively disallows the standard deduction and some itemized deductions. (cfs4me.com)
This represents the first federal increase to the highest income tax bracket since the federal income tax system was reformed in 1988. (canadianbusiness.com)
The federal income tax system is progressive, so the rate of taxation increases as income increases. (smartasset.com)