Q on associative binary operation

[Sarad AV]

hi,

how do we complete this table

Table shown may be completed to define 'associative'
binary operation * on S={a,b,c,d}. Assume this is
possible and compute the missing entries


*|a|b|c|d
---------
a|a|b|c|d
---------
b|b|a|c|d
---------
c|c|d|c|d
---------
d| | | |


Its clear for commutativity but I am a trifle confused
on how we do it for associativity.

Thank you.

Regards Sarath.

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