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# PT9.S3.Q8-13 (Logical Operators)

Alum Member
edited November 2017 3679 karma

Hi all,

In the explanation for this game board (https://7sage.com/lesson/inout-game-2-game-board-setup/?ss_completed_lesson=17878), JY uses group 3 logical operator, unless, to translate the lawgic. I thought that he would use group 4, cannot. How do we know which logical operator to use when there are two in the sentence?

• Member 🍌🍌
9361 karma

You can use either one and you will end up with the same thing.

N cannot be in unless L is in.

Group 3 translation:
Step 1) The logical operator: "unless"
Step 2) Identify the two main concepts: “N cannot be in” and “L is in”
Step 3) Assign symbols to the two main concepts: Here, “/N” for “N cannot be in” and “L” for “L is in.”
Step 4) Apply the translation rule: Here, pick an idea - “/N” - and negate it - “N” - and make it the sufficient condition.
N → L

Group 4 translation:
Step 1) The logical operator: "cannot"
Step 2) Identify the two main concepts: "N is in" and "unless L is in"
Step 3) Assign symbols to the two main concepts: Here, “N” for "N is in" and "/L" for "unless L is in"
Step 4) Apply the translation rule: Here, pick an idea - “N” - and negate it - “/N” - and make it the necessary condition.
/L → /N

I find Group 3 much simpler. As soon as "A cannot be in unless B is in," I immediately translate it as A → B because in order for A to be in, B must be in.

• Alum Member
3679 karma

@akistotle why does 'unless L is in' translate to '/L'?

• Member 🍌🍌
edited November 2017 9361 karma

"Unless" means "if … not" or "except if," so "unless L is in" means "the case where L is not in."

• Alum Member
edited November 2017 382 karma

Agreed with the above. I always found it easier to think of these types of statements as the below:

No N without L, which is equivalent to N requires L

N --> L

• Member 🍌🍌
9361 karma

@dcdcdcdcdc said:
Agreed with the above. I always found it easier to think of these types of statements as the below:

No N without L, which is equivalent to N requires L

N --> L

Yea. I learned this thinking that all those lyrics about "I can't live without you" basically means that "I need you." lol

So I go like, "Okay....N needs L...." whenever I see sentences like that.

• Alum Member
3679 karma

@akistotle @dcdcdcdcdc thzmks guys! I get it but it's still not cemented in my head just need more practice ugh learning this is so hard lol. So 'unless' should always be considered a / right?