not a prefix of a prefix if it is a prefix of a prefix search in the prefix of a prefix memory if a key is not found then a positive response is returned to confirm that the key is deleted anyway when a key is found it gets taken out of the pscb 12 first the second step is to try to collapse the pscb 39 s one needs to update the pscb 12 at the earliest point of the tree left most pscb 12 as one walks the tree so not to break the tree search that may be occurring on a different thread or branch starting with the direct table entry skip the number of bits specified in the direct table bit size starting from the most significant bit of the delete key based on the nbt at each node in the tree extract the 4 bits from the delete key to find the correct index into the next pscb 12 if the delete key is a full length key then by following the tree the last leaf in the tree should be the leaf to be deleted if the key is in the tree if the delete key is not a match then return a positive acknowledgement anyway if the delete key is a prefix then it could be encountered in one of two ways if the length of the delete key is less than or equal to the next bit to test or if the length of the delete key is less than the last leaf in the tree when the key to be deleted is a found leaf then the most number of pscb 39 s to collapse is one if the prefix of.