You will now complete your own first proof about subrelations.

"R ⊆ S" means that R is a subrelation of S. That means if R[x,y] holds, then also S[x,y].

The lemma proves that if R is a subrelation of S and S is a subrelation of T, then R must be a subrelation of T as well.

Try to complete the proof by inserting something for "{INSERT-SOLUTION-HERE}"!

Note that the proof markers "Assume", "Then" and "Hence" have different meanings:

- "Assume" opens an assumption in a proof. This assumption needs to be closed by "Hence".
- "Then" makes an additional derivation in a proof.

Line , Col

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