home	news	documentation	specification		implementation
foreword	milestones	version 2	version 2	(background - core - applications)	library	(static LDDL directory)
citations	visibility	version 1	version 1	(static HELM directory)	helena

Informal description: ""

{λ[a:Prop] .​ λ[b:Prop] .​ λ[n:({(b) .​ (a)} .​ imp ) .​ not ]} .​ <a> .​ {(λ[x:(a) .​ not ] .​ ({(x) .​ (b) .​ (a)} .​ th2 ) .​ n) .​ (a)} .​ et

Validation parameters: sort hierarchy = "Z2", kernel options = ""