If one were to thank someone for an action (i.e. 'Thanks for noticing' 'Thanks for participating.' etc..) Would that be an infinitive verb, a participle, or some other form?

Dankon, ke vi verb-is.

As Tom says, for example, mi dankas, ke vi venis - thanks for coming. (Tom's formula could be considers a truncation of Dankon pro tio, ke .. which is absolutely classically correct)

Another possibility - mi dankas/dankon pro (via) o-vorto.

For example, Dankon pro la atentigo pri .. - thanks for bringing this to my attention.

If Esperanto accepted a wider range of prepositions before infinitives, then dankon pro/pri infinitivo would also be a possibility. An expansion of the number of prepositions that can be used like this seems to be a point of growth in the language, but not yet fully established.

You can also use the durative of the verb, e.g.: Dankon pro donado

I was wondering about this myself; whether it would be acceptable to say, for example, "Dankon pro helpi min". I think the meaning of such a sentence would be perfectly understandable, but then, a lot of things with bad grammar are still clear in meaning.

Please pardon me, I don't mean to hijack the thread, but I'm also wondering if an infinitive can be used after "per"; as in, "Mi ofte ĝenas homojn per paroli pri aferoj, kiujn ili ne komprenas." I've used this construction several times, but still don't know if it is a proper construction.

Christa627:I was wondering about this myself; whether it would be acceptable to say, for example, "Dankon pro helpi min". I think the meaning of such a sentence would be perfectly understandable, but then, a lot of things with bad grammar are still clear in meaning.

Please pardon me, I don't mean to hijack the thread, but I'm also wondering if an infinitive can be used after "per"; as in, "Mi ofte ĝenas homojn per paroli pri aferoj, kiujn ili ne komprenas." I've used this construction several times, but still don't know if it is a proper construction.

Infintive clauses are nominal by nature and can hence appear almost everywhere a noun can appear. They can be subjects (Resti kun leono estas danĝere). They can be objects (Kiu kuraĝas rajdi sur leono?). They can be the complement of a prepositional phrase (Mi pensas, ke ŝi ne havas multe por forplenumi).
All of the above examples are Z'ian. No bad grammar anywhere.

"Mi ofte ĝenas homojn per paroli pri aferoj, kiujn ili ne komprenas." I've used this construction several times, but still don't know if it is a proper construction.

Christa, in classical Esperanto this would be ...parolante pri aferoj, kiujn ili ne komprenas or ...per parolado pri aferoj, kiujn ili ne komprenas.

For some reason (I have never got to the bottom of this) the range of prepositions classically used before infinitives is limited. At one time even sen + infinitive was consider controversial (now it it is fully accepted).

There are a few examples in the Tekstaro in recent texts of pri + infinitive:

temis pri telefona konsultado pri savi perditan leteron en la komputilo
Alico ne havis momenton en kiu pensi pri haltigi sin antaŭ ol ŝi trovis sin falanta
La ideo pri aktivigi FEJO-n naskiĝis dum la
ke la greka edukadministro eĉ ne sonĝas pri peti financan ekvilibraĵon
ĉar temas pri kolekti spurojn

So it looks as though this usage is becoming established, but the Tekstaro does not support per+infinitive (except where the the infinitive is quoted eg traduki tiun vorton per 'malhelpi' ).

Perhaps some clever grammarian can come up with an explanation of why there are hundreds of examples of por + infinitive, but per + infinitive is avoided.

sudanglo:

"Mi ofte ĝenas homojn per paroli pri aferoj, kiujn ili ne komprenas." I've used this construction several times, but still don't know if it is a proper construction.

Christa, in classical Esperanto this would be ...parolante pri aferoj, kiujn ili ne komprenas or ...per parolado pri aferoj, kiujn ili ne komprenas.

For some reason (I have never got to the bottom of this) the range of prepositions classically used before infinitives is limited. At one time even sen + infinitive was consider controversial (now it it is fully accepted).

There are a few examples in the Tekstaro in recent texts of pri + infinitive:

temis pri telefona konsultado pri savi perditan leteron en la komputilo
Alico ne havis momenton en kiu pensi pri haltigi sin antaŭ ol ŝi trovis sin falanta
La ideo pri aktivigi FEJO-n naskiĝis dum la
ke la greka edukadministro eĉ ne sonĝas pri peti financan ekvilibraĵon
ĉar temas pri kolekti spurojn

So it looks as though this usage is becoming established, but the Tekstaro does not support per+infinitive (except where the the infinitive is quoted eg traduki tiun vorton per 'malhelpi' ).

Perhaps some clever grammarian can come up with an explanation of why there are hundreds of examples of por + infinitive, but per + infinitive is avoided.

I am not a clever grammarian, and what I say now certainly does not explain everything about every preposition's affinability to infinitive. But concerning "pri", this preposition acts a bit like quoting by itself. So using it with or without quotation marks doesn't make much differnce. On the other hand traduki tiun vorton per "cerbumi" would have a totally different meaning without quotation marks on "cerbumi".

Perhaps some clever grammarian can come up with an explanation of why there are hundreds of examples of por + infinitive, but per + infinitive is avoided.

I wonder if this may have something to do with usage in European languages. In my experience most Romance and Slavic languages generally allow only certain prepositions before infinitives. Perhaps speakers of those languages, when using Esperanto, are hesitant to use other prepositions even where comprehensible, since they would sound so bizarre in their native tongues.

For example, in Russian por + infinitive is normal, but per/pri + infinitive is never possible because those prepositions require a change of case - something infinitives don't do.

For me, at least, using per/pri + noun[-ado] just "looks" much more natural; I would rarely intuitively choose an infinitive for those constructions. On the other hand, I would have no trouble understanding the intended meaning.

Tempodivalse:I wonder if this may have something to do with usage in European languages.

In my language, Swedish, the pattern is similar to the one in Esperanto, only a bit more permissive.

According to Detala gramatiko here at lernu! only por, anstataux and krom - and perhaps also sen - can stand with infinitive. (Pri is not mentioned.) In Swedish not only these five but also the ones normally said to correspond to de, al, el, en, inter, kontraux and post can have infinitive. These prepositions normally indicate place or direction, but seemingly when they are used with an infinitive their meening is more abstract. Translating a sentence with the Swedish preposition "i" followed by an infinitive into Esperanto, I would not use en, but rather choose pri.