fact: Definition nonvoid (I : interval) : CProp := match I with | realline => True | openr b => True | openl a => True | closer b => True | closel a => True | olor a b => a [<] b | olcr a b => a [<] b | clor a b => a [<] b | clcr a b => a [<=] b end.
imports: CoRN.ftc.NthDerivative