'In addition' and 'also' in one sentence? 'Helped improve' or 'helped to improve'?

[galois]

Hello friends, I have a couple of doubts regarding the correct writing of some sentences. I would greatly appreciate your help.
First, is it correct to use 'In addition' and 'also' together in one sentence?

In consequence, observe that an irreducible code and a reducible code are different codes in general. In addition, note that the irreducible codes defined here are also different from the codes in [ref.] defined as one-weight irreducible cyclic codes.

Where [ref.] is just a reference to another paper.
On the other hand, in the following sentence, should I say 'helped improve' or 'helped to improve'?

The authors would like to thank the anonymous reviewers for their valuable comments and suggestions that helped improve/helped to improve the quality of the paper.

Thank you very much for your help.

 

[probus]

I haven't the foggiest idea what reducible and irreducible codes are, but I assure you that you can certainly use both "in addition" and "also" in one sentence if you can think up a suitable context, in the same way you could use both "y" and "mas" or "ademas" in certain Spanish sentences. (Pease excuse me for omitting the accents from Spanish words. It's a big hassle to produce them with an English keyboard.)

"Helped improve" and "helped to improve" are identical. You can use either.

 

[tedmc]

"In addition" and "also" mean the same thing, so I would use either one but not both.

I think "help improve" is more common than "help to improve".