• InputAliases is an option for cells that allows you to define customized keyboard aliases for frequently used expressions.
• Using this option you can define aliases for any typeset expression, however complicated. For example, if you set InputAliases {"a1" SubscriptBox["a", "1"]}, then typing a1 enters the character into the notebook. • InputAliases is specified as a list with each element defining a single alias. The full form of each alias must be specified by its complete Publicon expression. • This option is typically specified in a style sheet.
{"a1" 
a1 
into the notebook.