
    {* We ought to allow "sheaf" to take a graded ideal as argument too!
    --and then we could add the example HH^1(sheaf IX)
    *}

    	the result should be a sheaf of ideals, not a sheaf of modules;
	and it seems sort of silly to invent the whole class of sheaves of ideals
	just so "sheaf I" will do something.  But, why not?
