I am trying to figure out a proper way of defining two constrained parameters and their priors:

I have x \in (0,1) and y \in (x, 1) and I would like to set up a beta-priors for x and y. What is not clear to me is where do I need to put bounds and/or explicit truncation?

For parameters block I though about using

```
parameters {
real<lower=0,upper=1> x;
real<lower=x, upper=1> y;
}
```

And as a prior something along lines

```
model {
x ~ beta(0.5 * 10, (1 - 0.5) * 10);
y ~ beta(0.75 * 10, (1 - 0.75) * 10);
}
```

But should I add explicit truncation somewhere here as x < y?

edit: I’m not fixated with the beta priors though, as long as I can easily provide some information about the prior means of x and y.