Self-maps of modules over the Steenrod algebra
John H. Palmieri
Journal of Pure and Applied Algebra 79 (1992), 281-291.



                                Abstract


   For a finite module M  over the Steenrod algebra A, we prove
the existence of a non-nilpotent element in Ext^{s;t}_A(M;M) "parallel to
the vanishing line."  We use this result to give a proof of Margolis'
construction to kill Pts-homology groups, at all primes.