## D&D 5e Lair Action Rule Interpretations for Young Black Dragons [duplicate]

• Do dragons of all sizes get lair actions and regional effects? 2 answers

Page 89 of the Monster Manual describes Lair Actions and Regional Effects. It says Regional Effects only apply to Legendary Black Dragons but does not say that for Lair Actions. Does that mean Lair Actions can be used for Young and Wyrmling Dragons?

## Is there a rule to recalculate the BODY of characters with cyberimplants?

For the Petrify spell, you only take into account the base BODY of the target, and ignore any kind or armor or protection the target may have since the spell targets the flesh only.

Following the basic rules, from the core rulebook, a full cyborg character a la Robocop, despite being not much more than a brain and spine, still has his full base BODY to resist the spell, since the cyber only makes one lose Essence.

Is there a rule that would allow to recalculate the BODY of a character for the purpose of the spell, taking into account the cyberimplants?

## Does timestamp protocol following thomas’s write rule allow non-view-serializable schedules in some cases?

I have came across following line in text book (Database System Concepts Textbook by Avi Silberschatz, Henry F. Korth, and S. Sudarshan $$6e$$) page no. 686:

Thomas’ write rule allows schedules that are not conflict serializable but are nevertheless correct. Those non-conflict-serializable schedules allowed satisfy the definition of view serializable schedules (see example box).

What I understood from above lines is that every schedule generated by timestamp protocol following thomas’s write rule is view serializable.

Now let’s take following little schedule: $$S: R_1(X), W_2(X), W_1(X)$$.

This schedule $$S$$ is allowed under timestamp protocol which follows thomas’s write rule.

And serialization order is $$R_1(X), W_1(X).$$

But I was not able to prove that it is view serializable.

Actually I think that it is non-view serializable because,

1. Consider serial order as $$T_1, T_2$$

Now final value of $$X$$ is being written by $$T_2$$. So not equivalent.

2. Next alternative serial order is $$T_2, T_1$$

here, $$R_1(X)$$ will read value of $$X$$ written by $$T_1$$ not original value which was there before start of both transaction. So this too is not view-equivalent.

## What definition of the noun “threat” do the rule books for D&D 5E use when it affects gameplay mechanics?

I have recently asked a question about Surprise where the unclear interpretation of the word “threat” in the sentence “Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.” seems to be the root of the problem. In a comment to an answer, I was adviced to look at Wiktionary’s entry for “threat” which defines it as:

1. An expression of intent to injure or punish another.
2. An indication of potential or imminent danger.
3. A person or object that is regarded as a danger; a menace.

While meaning 1 is certainly not the relevant one in the context of the rule for Surprise, the confusions seems to stem from the distinction between meaning 2 and meaning 3.

Are there any instances in an official rule book where it becomes clear in which sense the word threat is used in view of the game mechanics?

PS: I am aware that this problem can be solved by using pdf versions of the books and CTRL+f, but I do not have these files.

## How do I call a system like a grammar, but where a rule has to be applied to all matches at once?

For example, given rules $$\{ a \to x, a \to y \}$$ and input $$aa$$ , I am usually allowed to derive strings $$\{ xx, xy, yx, yy \}$$. I would like to restrict this to only performing “consistent” rewrites, so that the language would be like $$\{ xx, yy \}$$. It is evidently possible to synchronize rewrites in distant parts of a sentence within the usual formal grammar setting, but I wonder if this possibility is better explored under a different name or in a different arrangement.

I notice that context-sensitive grammars pose trouble with this “consistency” condition. For example, given a ruleset $$\{ aa \to x\}$$ and initial string $$aaa$$, I am not sure if I should allow anything to be derived. Then again, it is entirely possible that only some rules, and specifically some context-free rules, may be enhanced with consistency.

I am rather sure the system I have in mind defines a language, and even that I could with some thinking propose a formal way to rewrite a given grammar so that some select context free rules are made consistent. But I wonder if this is actually widely known under some other name.

## How to create rule to display multiple users in People Picker control

I have an IP 2010 List form. Below is the controls that I’m working with:

I have two controls. A dropdown that shows a list of Schemas. As shown above, I have rules made for if the Schema Test (TST), or any other Schemas for that matter, is selected then it populates the Assignee people picker control with the user associated with that schema.

The above works as expected with no issues. The challenge is this:

What rule, if there is any, can I use to populate the Assignee control if there are more than one user associated to the Schema?

For example, let’s say that Test(TST) has users John Doe and Jane Doe assigned. The expectation is that when Test(TST) is selected that the Assignee people picker would get populated with both John Doe and Jane Doe.

The issue is that I have tried to set the Assignee people picker control to allow to enter multiple users. The issue is that it will not populate more than one user when a Schema is selected with more than one user belonging to it.

Is it possible to accomplish?

## Are Context-Free Grammars with only one Production Rule always Unambiguous?

Consider the following (Context-Free) Grammars with only one production rule (not including the epsilon production):

• $$S \rightarrow aSb\space|\space\epsilon$$
• $$S \rightarrow aSSb\space|\space\epsilon$$
• $$S \rightarrow aSbS\space|\space\epsilon$$
• $$S \rightarrow aSaSb\space|\space\epsilon$$
• $$S \rightarrow aaSaaSbb\space|\space\epsilon$$
• $$S \rightarrow aSbScSdSeSf\space|\space\epsilon$$
• $$S \rightarrow aSSbcSd\space|\space\epsilon$$
• etc…

Are all these Grammars unambiguous? Will every Grammar with only one production rule (not including the epsilon production) always be unambiguous? It would seem so, but I’m not totally sure.

Grammars that only contain one unique terminal symbol could be ambiguous. (ex. $$S\rightarrow aSaSa\space|\space\epsilon$$) However, Grammars with at least two distinct terminal symbols seem like they should always be unambiguous.

I’ve tried showing that Grammars like these are $$LL(1)$$. However, it seems only Grammars of the form $$S \rightarrow aSb\space|\space\epsilon$$ are $$LL(1)$$. Grammars like $$S \rightarrow aSaSb\space|\space\epsilon$$ are not $$LL(1)$$. (Illustrated in the parse table below.)

Despite the example Grammar above not being $$LL(1)$$, it still seems to be unambiguous. Maybe it’s simply a matter of using a higher $$k$$ for $$LL(k)$$?

In short, are (Context-Free) Grammars with only one production rule (not including the epsilon production) and at least two unique terminal symbols always unambiguous?

I would really love some help, any at all would be greatly appreciated.

## What would happen if we added this rule to red-black trees?

So, I know that a normal r-b tree has a height of O(logn). What would happen is we let a red node have a red child if its parent is black?

Would the height still be O(logn)? Would you have to have a totally different insertion scheme to maintain the height?

## Where does the ‘Natural Language’ rule come from?

Frequently it is said (sometimes by me) that 5e’s rules expect the reader to use ‘natural language’ or the ‘normal’ meaning of words when interpreting any words in the rules texts the game doesn’t specifically define. Where does this idea come from? If it is a rule, where is it found?

## Is structural induction a particular case of (co)induction rule for an inductive predicate?

What is the relation between the principle of induction on terms:

If, for ech term s,   given P(r) for all immediate subterms r of s  we can show P(s), then P(t) holds for all t 

and the inductive or coinductive induction principles? For instance, if I write:

inductive evn where "evn 0" | "evn x ⟹ evn (x+2)"  thm evn.induct 

in Isabelle I get the principle:

evn ?x ⟹ ?P 0 ⟹ (⋀x. evn x ⟹ ?P x ⟹ ?P (x + 2)) ⟹ ?P ?x 

Before, I thouth that these were two different styles of proof. But know I believe they should be related in some way since after all a term grammar can be given as an inductive predicate.