atlas interaction from June 2, 2020 seminar

[Davids-MBP-100:~] dav% atlas all
This is 'atlas' (version 1.0.8, axis language version 1.0),
the Atlas of Lie Groups and Representations interpreter,
compiled on Jun  2 2020 at 09:11:49.   http://www.liegroups.org/
atlas> set G=U(4,2) 
Variable G: RealForm
atlas> set p=G.trivial
Variable p: Param
atlas> p
Value: final parameter(x=119,lambda=[5,3,1,-1,-3,-5]/2,nu=[5,3,0,0,-3,-5]/2)
atlas> set mylambda = (p.lambda + p.x.involution*p.lambda)/2
Variable mylambda: ratvec
atlas> mylambda
Value: [  0,  0,  1, -1,  0,  0 ]/2
atlas> set q=p*0
Variable q: Param
atlas> set q0=first_param (finalize(q))
Variable q0: Param
atlas> set mylambda = (q0.lambda + q0.x.involution*q0.lambda)/2
Variable mylambda: ratvec (overriding previous instance, which had type ratvec)
atlas> mylambda
Value: [  1,  0,  0,  0,  0, -1 ]/2
atlas> {this looks like what I had}
atlas> q0  
Value: final parameter(x=37,lambda=[1,1,-1,1,-1,-1]/2,nu=[0,0,0,0,0,0]/1)
atlas> {note different x, nu=0; explanations in OneNote notes}
atlas> quit
Bye.