[deduce].
'Command examples:     CHECK|: deduce.'.
'                      CHECK|: deduce c#1.'.
'                      CHECK|: deduce x>0 or x<0 from [1,4].'.
''.
'This command invokes truth-table logical deduction.  You must state the'.
'formula you wish to prove and provide a list of (zero or more)'.
'hypothesis numbers to be used.'.
