What is going on with 書けている? What is Potential Form+ている?

Question

I'm having difficulty in understanding 書けている (initially observed from an answer to "パソコンが　得意だ/わかる/上手だ"). Also observed from SPACEALC:

• この小説は上手に書けている。

• 最もよく書けている記事。

• いくつかのスペルミスを除けば、その小論文はよく書けている。

I thought that the sentence would have been この小説は上手に{書いている・書いてある}。instead.

(Q1) What is the difference between 書いている and 書けている? And what does 書けている mean?

(Q2) What is the grammatical composition of 書けている? Is it potential form+ている?

(Q3) Is this pattern of potential form+ている productive? I.e. can it be arbitrarily extended to other verbs with a similar result?

Answer 1

Yes, it is the potential form of 書く in the progressive.

These phrases are often used in the form 上手に/よく+[verb in potential form]. By itself, the potential form indicates that you are able to do something, and in combination with 上手に/よく, it means you did it well.

よく読めた (praising a primary school kid on his 音読 reading out loud)

上手にできた etc.

The progressive is used for saying that the result is well written. よく書けたね would mean more the act of writing was well done, but says little about the result... There have been questions on the usage of the progressive tense with well-written answers. I'll try to find a link and post it here.