Known typos in 
A. V. Knyazev and Olof Widlund, Lavrentiev Regularization + Ritz Approximation = Uniform Finite Element Error Estimates for
Differential Equations with Rough Coefficients. 
Mathematics of Computation, posted on July 13, 2001, 
<a href="http://www.ams.org/journal-getitem?pii=S0025-5718-01-01378-3">
S0025-5718-01-01378-3</a>
(to appear in print). 

<p>
In 3rd and 4th formulas on page 8
<br>
||Pu-w||=||inv(B-wI)(A-wI)(Pu-w)|| should be
<br>
||Pu-w||=||inv(B+wI)P(A+wI)(Pu-w)||
<br>
and 
<br>
<=(1/(c+w)))||(A-wI)(Pu-w)|| should be
<br>
<=(1/(c+w)))||(A+wI)(Pu-w)|| 
<br>
although the conclusion is correct.