# Sequent calculus - proofs as trees or sequences

First at all, I am new at proof theory, so excuse this perhaps redundant question.

I am wondering what is the 'most appropriate' definition of a proof in a sequent calculus (e.g. LK). Proofs as trees or proofs as sequences of sequents?

Does one of the representations have advantages in proofs about the calculus (I am especially thinking of induction on proof length, etc.)

Regards

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In proof complexity the DAG is the standard version and the tree version is denoted by adding a $*$ superscript. For example, the tree version of bounded-depth Frege (a propositional proof system equivalent to $PK$) is denoted by $bdFrege^*$.
In classical proof theory it doesn't matter that much which definition you use for $LK$. Both are fine, however I think the tree version is the more standard one (it seems to be the one used in proof theory textbooks).