+ <news date="2014 January 20.">
+ Parametrized slicing for local environments
+ comprises both versions of this operation
+ (one from basic_1, the other used in basic_2 till now).
+ </news>
+ <news date="2013 August 7.">
+ Passive support for global environments.
+ </news>
+ <news date="2013 July 27.">
+ Reaxiomatized β-reductum as in extended β-reduction
+ </news>
+ <news date="2013 July 20.">
+ Context-sensitive extended strong normalization