SPARQL MIN on string - sparql

Question

I am studying SPARQL and there is this example on the documentation page:
PREFIX : <http://people.example/>
PREFIX : <http://people.example/>
SELECT ?y ?minName
WHERE {
:alice :knows ?y .
{
SELECT ?y (MIN(?name) AS ?minName)
WHERE {
?y :name ?name .
} GROUP BY ?y
}
}
From this dabase:
#prefix : <http://people.example/> .
:alice :name "Alice", "Alice Foo", "A. Foo" .
:alice :knows :bob, :carol .
:bob :name "Bob", "Bob Bar", "B. Bar" .
:carol :name "Carol", "Carol Baz", "C. Baz" .
There is says that this query:
"Return a name (the one with the lowest sort order) for all the people that know Alice and have a name."
and the output is:
y minName
:bob "B. Bar"
:carol "C. Baz"
But I can't understand how "B. Bar" is smaller than "Bob", for example. I cannot understand what the docs means with "lowest sort order".
For me the output should be:
y minName
:bob "Bob"
:carol "Carol"
Thank you for your help.