Question about Triple Pattern Fragment (TPF) and hydra:filter

Hi there,
This is my first email to HYDRA community. If there are anything incorrect,
i'm sorry in advance.

Currently, I'm working on my project which relate to HYDRA vocabulary.
I would like to define my API description that allows the client to query
collection's members with certain property.
The assumption is that a client know:
1) the collection URL (i.e., <http://example.org/collection>).
2) the vocabulary of such property (e.g., rdfs:label,  dcterms:modified).
3) hydra vocabulary such as hydra:filter, hydra:template, and hydra:mapping.

>From what I known, hydra:filter [1] is the vocabulary that is used to query
members of collection.
Linked Data Fragment (LDF) [2] is more general concept that used to query
any triples depend on the resource that attract to.
Triple Pattern Fragment (TPF) [3] is implementation of LDF, which is based
on HYDRA vocabulary.

In the example of TPF [3], it is used against dataset.
But I want to use TPF with hydra:Collection.
Therefore, i replace the hydra:search with hydra:filter and attract them to
the collection (i.e., <http://example.org/collection>)
The details of my designed API show as below.

The question is whether this API is valid?
Would you have a suggestion?

###API description#####
<http://example.org/collection>
    hydra:filter [
        hydra:template "http://example.org/collection{?p}";
        hydra:variableRepresentation  hydra:BasicRepresentation ;
        hydra:mapping
                       [ hydra:variable "p"; hydra:property rdf:predicate ]
    ].
###Client request URL####
http://example.org/collection?p=http%3A%2F%2Fwww.w3.org%2F2000%2F01%2Frdf-schema%23label

Note that. rdfs:label  ==  http%3A%2F%2Fwww.w3.org
%2F2000%2F01%2Frdf-schema%23label
####Response#########
<http://example.org/collection/member1>  rdfs:label "member1"@eng .
<http://example.org/collection/member2>  rdfs:label "member2"@eng .
<http://example.org/collection/member3>  rdfs:label "member3"@eng .

[1] https://lists.w3.org/Archives/Public/public-hydra/2014Feb/0173.html
[2]
http://www.hydra-cg.com/spec/latest/linked-data-fragments/#linked-data-documents
[3] http://www.hydra-cg.com/spec/latest/triple-pattern-fragments/

Regards.