I just wanted to check if I´m understanding a certain concept correctly.

This is what´s written in one of the books I´m using:

"-malý, -meli" bazen cümleye olasýlýk anlamý da katar." I think it means that -meli/-malý suffixes add the meaning/understanding of probability to some sentences.

And the following examples are given:

Uçak Ýstanbul´a inmiþ olmalý.

Ders zili çalmýþ olmalý.

Ahmet, beðendiði elbiseyi almýþ olmalý.

So my question is, first of all, am I correct in translating the sentences as:

The plane to Istanbul should have landed.

The doorbell should have rung.

Ahmet, should have bought clothes that he likes.

And my second question is, if in the participle -miþ would be the one usually used in this type of sentences. For example, would it be correct to say: Arkadaþým gelmiþ olmalý. for "My friends should have come (meaning he´s probably here)"?

The "-miþ" is a source of miþ-ery to me lol.

Thanks in advance for any feedback/corrections.

 Both should have and must have can be used and they are correct...

Regarding your misery, we use -miþ when we assume things, or hear from another person, but not witnessed ourselves...

Ali eve gelmiþ bile.. means you were not expecting that he would come this early, you open the door, you see him, and turn around to tell your friend that he has already come back to home....

Orada bir kaza olmuþ - You haven´t seen the accident, but somebody has seen it and told you, and now you are narrating it to someone else.

Likewise in your examples, you haven´t seen the plane landing and you haven´t heard from anyone, but you know the plane was to land at a particular time, so you are assuming that the plane must have landed, because it was supposed to land at - 6 o´clock and now it is 6;30.

Thank you Merih. Let me ask one follow up question to that then.

Is there a whole lot of difference between saying "Uçak inmiþ" and "Uçak inmiþ olmalý" - what I´m thinking is that in the second example you´re making the assumption about the plane yourself and in the first somebody told you about it? Is that right? 

 Yes, exactly, when you say uçak inmiþ, you are certain that it landed as somebody told you, or you got a call from the person in the plane saying that he landed.  The second one, olmalý, you have no certainaty but you just think or assume that it landed.

 And thank you once again

-miþ problem.

I am only a beginner and had trouble in diffrentiating between ... ´... should have come ...´, & ´... has definitle come ...´

I came accross a very good explanation by in ´Turkish´ by Prof. G.L. Lewis [ISBN 0340 05828 5] & ´Turkish´ by David and Celen Plooard [ISBN 070 243422 4]

> You can use ´-miþtir´ when you are not sure that something has happened, but expect it to be the case e.g:-

EXPECTATION: ´Bir saat önce çýktý.  Þimdi oraya gelmiþtir´ - She left an hour ago (and) she must have arrived there by now.

[Prof. G.L. Lewis explains  - The uncertainty implied in this comes NOT from -miþ, but from -tir [-dir]!!] 

CERTAINTY:  ´Ankara treni ikinci perona gelmiþti´ - The train from Ankara has arrived on platfrom two.

[The Prof. explains that the suffix -ti is only used when the action has deffinitely been completed!]

Thus  -mali bit is made redundant.  But please do not take my word for it, although this has cleared my problem.  Unfortunately I can´t even speak Turkish fluently.

[Remember > Arabic is a language, Farsi is sweetmeat, Turkish is an art]

Tazx1

gelmiþtir - gelmiþ olmalý is almost the same. 

Thank you.  I will take your word for it and remember it.

Tazx1

I don´t want to complicate the issue but let me add this crucial detail about -miþtir.

"-miþtir" definetly corresponds to "must+have+ verb 3" which implies a probability or a guess. It means exactly the same with "-miþ olmalý".  

but -miþtir might also imply "certainty" in some contexts, especially in formal or official circumstances.

For example,

Þirketimiz fiyatý düþürmek için müzakerelere baþla-mýþtýr. (A memo or a public declaration which means "Our company has started negotiations in order to reduce the prices."

There is no sense of probability or estimation here. It means exactly the same with past tense with -di, but the sentence is meant to be a formal declaration hence uses -miþtir instead.

I think this is not even an exception and you will come across with this usage almost everyday in newspapers and in news broadcasts.

 Good addition.