Why are MAT files created by Julia significantly larger than those created by Matlab?

Thank you all for the very helpful discussion!

Tim,
Interesting to hear about that.

Concerning the best way to write the code, I assume you meant the below?
matwrite(F1, Dict(
“x” => B[:,1],
“y” => B[:,2],
“f” => B[:,3]
); compress = true);

My question is why they use a semicolon, instead of a comma after the dictionary variable? Both seem to work though.