Vestitor:I'm troubled by this.

I wouldn't worry, it's actually all very simple. bryku is flat out wrong that adjectives function as an equivalent to genitive case, and the example provided from PMEG is being misused to prove this.

"Reĝa palace" means something like "kingly palace". Of course you can also describe that as "a palace which belongs to a king", just as PMEG chooses that description, but that doesn't make it the genitive.

bryku:Can you read? It was "Aa B", not "mia Aa B" or something else.

Two points.

1) No need to be rude.

2) Whether it's "Aa B" or "mia Aa B" is irrelevant. You said that adjectives may be used as an equivalent to the genitive, so if you want to propose "patrina malsano" for "mother's desease" then you also need to allow for "mia patrina malsano" for "my mother's desease". If you don't allow this, and insist it must be formed in some other way, then you're just introducing an arbitrary rule and your argument that Aa is equivalent to A's falls apart.

apriliss:In English we can say something which belongs to something else by "A's B" instead of "B of A". Is the similar way of saying possible in Esperanto too? Cause It doesn't seem to be except the specific possessives (mia, ilia...)

ekz
- My sister's boy is gonna come.
- That book is John's diary.
- My mother's disease has gotten worse.

In addition to the possessive pronouns (mia, ilia...), there are also the correlatives in -es (ties, kies...). Beyond that, I would say erinja is correct. While an argument can be made for -a as a possessive ending, it cannot be applied in all circumstances where English uses -'s, and in a number of places would likely be ambiguous or hard to parse, while using "de" is much safer and more readily understood.

Vestitor:I'm troubled by this. If it's inserted in sentences it is not clear what is exactly meant:

Li realigis ke tiu estis la reĝa palaco.

Does that mean:

1. He realised that it was the king's palace?
2. He realised it was the royal palace? (reĝa = 'kingly' = royal).

'Li realigis ke tiu estis la reĝa palaco'. I don't understand this sentence, too. Would it be same like: 'Li realigis ke tiu estis reĝo sia palaco'? ('reĝo sia' = Lidepla 'rega-ney')

bryku:Sister's room = fratina ĉambro

John's ball = Johana pilko

...

PL: pokój siostry; siostrzany pokój.
That's what they all meant by not being clear - -a can either mean adjective derived from the base noun, or this strange possessive.
In some cases, it may be more or less clear (because e.g. above the 'sisterish room' doesn't make sense - but in the other of the examples 'patrina' may mean 'maternal') but as it's not a common construction, it's more likely that it will cause confusion.
And that's what you mentioned yourself:

Ĝenerale la signifo de tia A-vorto multe varias laŭ la kunteksto:
reĝa palaco = “palaco kiu apartenas al reĝo” = king's palace

'Regxa' is an adjective that actually means more or less what the possessive form does - we may assume that in a 'royal palace' ('kingly', if we use adjective made from 'king', not 'royal' derived from French) there's a king (or that it was build by a king, or that there was a king once).

In Esperanto, you have to use de to show possession.

The book of my friend.
La libro de mia amiko.

Sister's room = fratina ĉambro

John's ball = Johana pilko

Fratina ĉambro = A room with the qualities of a sister. Maybe, the room is designed to be appealing to sisters in some way. Maybe the room is for a sorority. This does not show ownership.

Johana pilko = Same thing here. Maybe, the ball has a picture of Johano on it. But it does not show ownership.

tommjames:

Vestitor:I'm troubled by this.

I wouldn't worry, it's actually all very simple. bryku is flat out wrong that adjectives function as an equivalent to genitive case, and the example provided from PMEG is being misused to prove this.

"Reĝa palace" means something like "kingly palace". Of course you can also describe that as "a palace which belongs to a king", just as PMEG chooses that description, but that doesn't make it the genitive.

I NEVER said that it replaces English genitive. It is why I asked if "you can read", because you are using facts I have never referred to. I just said, that SOMETHIMES it is useful to use such a form. That is all of it. The rest of your text is nonsense, because it refers to Esperanto as if it was English - languages are not codes an can NOT be translated word for word. What is good in English does not necessarily be good in Esperanto and vice versa.

Adjective function can and is used for possessiveness:

mia domo = domo de mi
via patro = patro de vi
lia libro = libro de li

"mia" is the adjective, is it not?

Alkanadi:

Sister's room = fratina ĉambro

John's ball = Johana pilko

Fratina ĉambro = A room with the qualities of a sister. Maybe, the room is designed to be appealing to sisters in some way. Maybe the room is for a sorority. This does not show ownership.

Johana pilko = Same thing here. Maybe, the ball has a picture of Johano on it. But it does not show ownership.

My friend, you are writing nonsense. By analogy:
if "fratina ĉambro" is the room of qualities of a sister, than "via ĉambro" has qualities of some you.

Alkanadi:Johana pilko = Same thing here. Maybe, the ball has a picture of Johano on it. But it does not show ownership.

Oh, really? Then "via pilko" is not yours.

bryku:I NEVER said that it replaces English genitive.

And I never said that you did say that. I said that you said it is equivalent to the genitive, or more specifically, that Xa is equivalent to X's.

Erinja said "There's no equivalent to the 's of English." And you responded with "Actually there is: Aa B". I think that's pretty clear.

To my mind it makes no sense to refer to something as an equivalent if all you're talking about is something that can sometimes function as a substitute. But whatever, no need to get hung up about that.

bryku:The rest of your text is nonsense, because it refers to Esperanto as if it was English

No, it does not. It refers to your claim that Aa is equivalent to A's.

A's is an English construct, so obviously I'm going to reference the English genitive.

bryku:Adjective function can and is used for possessiveness:

mia domo = domo de mi
via patro = patro de vi
lia libro = libro de li

"mia" is the adjective, is it not?

No idea why you're mentioning this. It was already established in the first post of this thread that possessive pronouns are an exception to the need to use "de" for the genitive. Whether or not you consider them adjectives, it has no bearing on the discussion at all.

Like I said in my first post here, use of adjectives (besides possessive pronouns) is rarely, if at all, a suitable alternative to "de". Whatever you think you will gain from "expressiveness" or whatever will be heavily offset by the confusion that you'll likely create.

bryku:if "fratina ĉambro" is the room of qualities of a sister, than "via ĉambro" has qualities of some you.

Non sequitur. Possessive pronouns do not work exactly like adjectives. "Via ĉambro" means "your room", and nothing else. If you think it has a meaning like "vieca ĉambro", you need to brush up on basic grammar.