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Informal description: ""

{λ[a:Prop] .​ λ[b:Prop] .​ λ[o:{(b) .​ (a)} .​ or ] .​ λ[e:{(b) .​ (a)} .​ ec ]} .​ <{(b) .​ (a)} .​ orec > .​ {(e) .​ (o) .​ ({(b) .​ (a)} .​ ec ) .​ ({(b) .​ (a)} .​ or )} .​ andi

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