Compute canonical cover using armstrong's axioms

question:Determine the canonical cover using Armstrong’s Axioms. Give the axioms that you use to arrive at each step.

R = (A, B, C, D, E, F) Fdependencies = {A -> B, A -> C, CD -> E, CD -> F, B -> E}

I know armstrong's axioms:union, decomposition, pseudotransitivity, reflexivity, augmentation, and transitivity. I also know what canonical cover is. However, I do not know how to use armstrong's axioms to reach an answer for 开发者_运维知识库this particular question-- I thought you would usually use armstrong's axioms to compute F+, not the cc. Thanks for the help.

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The top answer showing up when I googled "canonical cover" :

http://www.koffeinhaltig.com/fds/ueberdeckung.php

Computing F+ is itself usually not very interesting. Computing some minimal set that is provably equivalent may be a bit more interesting, allthough I have my doubts.

Note (not your actual question, but I'll mention it nonetheless) that while your problem is about "minimizing the attribute sets on both sides of the FDs", the most useful use of Armstrong's axioms is to compute FDs that have minimal attribute sets on the left, but maximal on the right (=all attributes). That gives you all the (minimal) keys, and thus gives you an easy way to check the NF.