Neither activating an ability that creates a regeneration shield nor casting a spell that creates a regeneration shield is the same as regenerating a permanent. Effects that say that a permanent can’t be regenerated don’t preclude such abilities from being activated or such spells from being cast; rather, they cause regeneration shields to not be applied.
July 3, 2020 · Core Set 2021
If a player is instructed to search a hidden zone for cards that match an undefined quality, that player may still search that zone but can’t find any cards.
May 3, 2019 · War of the Spark
If an effect would cause a player to shuffle one or more specific objects into a library, that library is shuffled even if none of those objects are in the zone they’re expected to be in or an effect causes all of those objects to be moved to another zone or remain in their current zone.
January 25, 2019 · Ravnica Allegiance
If an effect would cause a player to shuffle one or more specific objects into a library, that library is shuffled even if none of those objects are in the zone they're expected to be in or an effect causes all of those objects to be moved to another zone or remain in their current zone.
April 27, 2018 · Dominaria
If an effect would cause a player to shuffle one or more specific objects into a library, that library is shuffled even if none of those objects are in the zone they’re expected to be in or an effect causes all of those objects to be moved to another zone or remain in their current zone.
September 30, 2011 · Innistrad
rule 701.19c not present in this release
June 17, 2011 · Commander 2011
A player wins a clash if that player revealed a card with a higher converted mana cost than
February 4, 2011 · Mirrodin Besieged
A player wins a clash if that player revealed a card with a higher converted mana cost than all other cards revealed in that clash.
October 1, 2010 · Scars of Mirrodin
A player wins a clash if that player revealed a card with a higher converted mana cost than
February 1, 2010 · Worldwake
A player wins a clash if that player revealed a card with a higher converted mana cost than all other cards revealed in that clash.