R $=$Team$,$ Opponent, Day, Player, Number, Positiong$$ with the following set of FDs: $(1)$Team$,$ Day$--$ Opponent, $(2)$Opponent$,$ Day$--$ Team $($each team plays at most one game in a day$).(3)$Team$,$ Player$--$ Number $($a player has one number in the team $).(4)$Team$,$ Day, Number$--$ Player $(5)$Day$,$ Team, Opponent, Player$--$ Position $($each player that for a game is assigned one position in that game$).$ Answer$1.$What are the candidate keys of R$?$ Is it correct to use the following step to find candidate key?

Step$1$:Day is not appear in RHS$.$

If $($Day$)+=$ R then $($Day$)$ is the only candidate key.

$($Day$)+=$ Day $!=$ R

So $\{$Day$\}$ is not candidate key.

Step $2$:

The combination who can determine all the attribute is a candidate key.

Day is not in the RHS$,$ so Day is part of candidate key. We just need to list the closure of all the possible combination of the attribute which include Day and see which combination can determine all the attribute.