periodic review systemperiodicalperiodicityperiodicity of a functionperiodogramperiority rulesperipheralperipheral deviceperipheral equipmentperipheral speedperiphericperipheryperiphery of a circlepermanencepermanence of formspermanence of functional relationspermanentpermanent moldpermanent motionpermanent storagepermanentlypermeabilitypermissedpermissiblepermissible valuepermitpermittivitypermutabilitypermutablepermutable elementpermutationpermutation grouppermutation group matrixpermutation group representationpermutation matrixpermutation representationpermutation tensorpermutation with repetitionpermuteperpendicularperpendicular bisectorperpendicular curvesperpendicular lineperpendicular linesperpendicular planeperpendicular planesperpendicular toperpendicularityperpendicularity conditionperpendicularly