Benchmark "michaeck" : Poisson problem with re-entrant corner

Material coefficients:	a1	a2	c
	1.	1.	0.
source term :	f
	1.
Boundary conditions:
Dirichlet - type:	u=0	(overall)

Typical behavior of estimated relative error:
Das typische Verhalten des geschaetzten Fehlers :

here some RUNs with times / iteration numbers / etc.



speciality on other boundary conditions : (Neumann/Dirichlet)

Material coefficients:	a1	a2	c
	1.	1.	0.
source term :	f
	1.
Boundary conditions :
Dirichlet - type:	u=0	(overall,except:)
Neumann - type:	du/dn=0	at y=0 x>0

Typical behavior of estimated relative error (WITHOUT stabilization): (Legende)
(break down witht NaN for "rg" and "Bg")

Typical behavior of estimated relative error (WITH stabilization): (Legende)