I would like to write down my lecture notes. The proofs of the theorems in this lecture are usually really big. It usually looks like this:

Theorem 1:Here comes the statement of the Theorem

Proof.

- Without loss of generality let us assume…
- Claim 1: Statement.

Proof:Blah blah \endOfInnerProofSymbol

- Claim 2: Statement.

Proof.Blah blah \endOfInnerProofSymbol\endOfProofSymbol

So my question is now, how can I make such nested proofs with another QED-symbol than the parent proof (maybe a filled square)?

## Best Answer

You can simply define a new environment

`subproof`

that mimics the behavior of`proof`

but uses a filled square instead of the default one.You can even give it the optional argument as in

so to print "Subproof" instead of "Proof".

MWE (note the

`\item`

after the outer`proof`

to let`enumerate`

start on a new line)