Hi, I read xA as x is a member of the set A. Is that not correct? In the linked example for #1, the notation LJ is used to show Luke is a member of the Jedi set.

If x is a member of the set A and a is a subset of B then x is a member of the set B is it not?

I see a contradiction in # 10

MW -> W

MW -> M

LSD -> /M

H -> LSD

mwLSD

It tells us Mr. White cooks Meth (MW-> M) and synthesizes LSD (mwLSD) BUT If you synth LSD you cannot cook meth (/LSD -> M). Which is it? Does he cook meth or not?

Is this a typo in the question or can we expect to be presented with questions that contradict themselves or am I missing something?

#help #feedback

I thought so to until I substituted words for the symbols.

A -> B

xA

-----

xB

All cats (a) are mammals (b). Jamie is a cat (xA). Therefore Jamie is a mammal (xB)

#help #feedback Would appreciate a detailed walk-though on how to chain together the individual pieces of question 2. It's a pretty difficult question compared to the other ones we've seen.

(Unable to edit above)

With the other keywords (unless, without, until, etc...) the condition you negate becomes the sufficient.

With these keywords (cannot, no, none, etc..) the condition you negate becomes the necessary condition.

e.g. 1

Perry Mason will continue his trickery unless the judge makes an order for him to stop

Sufficient: No Judge’s Order

Necessary: Perry Mason trickery

Lawgic: /Judge's Order -> Trickery , /Trickery -> Judge's Order

e.g. 2

Allan Shore cannot win a case if Denny Crane isn't with him

Sufficient: No Denny Crane

Necessary: Allan Shore cannot win

(notice that No Denny Crane isn’t a negation, that’s the original claim and "AS wins case is the negation of "Allan Shore cannot win")

Lawgic: /DC -> /AS wins case, AS wins case -> Denny Crane

Let me try and explain

They seem the same to me. The necessary condition comes immediately after "only" in both cases.

When we have sentences like "Only if Knights wield enchanted swords can they slay dragons." and we identify the necessary clause as "can slay dragons", does that mean slaying dragons is sufficient for a knight to bear an enchanted sword? Surely it doesn't right? I'm getting a bit confused because of how we translate it to lawgic: sufficient -> necessary.

This one hurt my brain. Here's how I eventually understood it.

The sentence does not say that arriving more than 5 minutes after the bell guarantees a student will be cited as late.

Thus, we must assume there are situations where one can be more than 5 minutes late and not be cited as late.

Isn't the verb in the archaeologists sentence "helped discover" as helped is a catenative verb (linking verb) ?

I still don't follow why it's not an argument. I would have thought the conclusion (what you want me to believe) is "I miss you" and it is supported (weakly) by "I'm hugging you". #help