Cardinality of the statement

[suste88]

What is the cardinality of this statement { x|x is a string over {a, b, c} and |x| <= 2}

 

[MathLover1]

The set described is { a, b, c, aa, ab ,ac, ba, bb, bc, ca, cb, cc} over |x| <= 2

and this set has cardinality 13 because there are 13 things in it

 

[nycmathguy]

The set described is { a, b, c, aa, ab ,ac, ba, bb, bc, ca, cb, cc} over |x| <= 2

and this set has cardinality 13 because there are 13 things in it

Wow! I didn't know that you can do sets. Impressed. You know set theory? This is something for me to explore in the future after calculus 3.

 

[MathLover1]

first time I learned about sets is in high school, 1965-69

 

[nycmathguy]

first time I learned about sets is in high school, 1965-69

There is a course called Set Theory, which is not the same as high school sets.

 

[MathLover1]

of course college set theory is more complex (nowadays considered as a foundation of all other branches of math , and the mathematical science of the infinite), and not same as high school

 

[nycmathguy]

of course college set theory is more complex (nowadays considered as a foundation of all other branches of math , and the mathematical science of the infinite), and not same as high school

It's an interesting course but not so easy to grasp.

 

[MathLover1]

it's not hard
here is one link for you, I think you will like it

https://courses.lumenlearning.com/atd-hostos-introcollegemath/chapter/set-theory/

 

[nycmathguy]

it's not hard
here is one link for you, I think you will like it

https://courses.lumenlearning.com/atd-hostos-introcollegemath/chapter/set-theory/

Thanks for the link. However, I want to study one course at a time. Note: suste88 didn't thank you for your effort and reply here. This is what I'm talking about. Boring site. You know what, I will post some questions for you. Maybe you are bored? Let me look for some questions that I don't know how to solve in the David Cohen precalculus textbook. Look for 3 or 4 questions in about 15 minutes.

 

[MathLover1]

it's part of precalculus

http://athsauhmath.weebly.com/uploads/2/8/5/9/28591589/set_theory.pdf

 

[nycmathguy]

it's part of precalculus

http://athsauhmath.weebly.com/uploads/2/8/5/9/28591589/set_theory.pdf

The basics of set theory is part of precalculus not the entire set theory course. Set theory is very intense at the college level. I can solve some basic set theory problems but this does not mean that I know the actual set theory course.

 

[Country Boy]

The set described is { a, b, c, aa, ab ,ac, ba, bb, bc, ca, cb, cc} over |x| <= 2

and this set has cardinality 13 because there are 13 things in it

By the way, it is the set that has cardinality 13, not the statement!