Is there a symbol for "multiple"?
You could use ">1 case" which can be pronounced "More than one case"
This would mean that the breakdown you give would have the form of a programming Case statement which would read something like
Select Case numOfCases
Case 0
Call Sol1
Case 1
Call Sol2
Case >1
Call Sol3
Case Else
print "Number of cases cannot be negative"
End Case