Is it obligatory to perform the forgetfulness prostration (sujud al-sahw), either before or after the salaam, if a worshipper inadvertently recites an audible prayer silently or vice versa?

The majority of scholars hold that both audible and silent recitation, each in its proper place, are Sunnah (recommended practice), while the Hanafis consider them wajib (obligatory). The Malikis and Hanbalis (in one narration) deem sujud as-sahw (prostration of forgetfulness) Sunnah for one who inadvertently, not intentionally, violates the Sunnah. As for the Hanafis, they consider sujud as-sahw obligatory for one who omits the audible or silent recitation, which they deem obligatory. The Shafi'is do not consider sujud as-sahw incumbent upon one who violates this Sunnah, citing as evidence the hadith of Abu Qatadah that the Prophet, peace and blessings be upon him, would sometimes let the Companions hear a verse during the Dhuhr prayer.