maths.free › Category Theory › Universal properties, limits and adjunctions
Universal properties, limits and adjunctions
Products, coproducts, limits and the adjunctions that unify constructions.
A product is defined by what maps into it, not by what it is made of; the same shape of definition gives limits, colimits and free objects. Adjoint functors pair a "free" construction with a "forgetful" one. Picture it: the lcm of 4 and 6 is the least common multiple in the divisibility order, a categorical join. Think it: Yoneda: an object is determined by the arrows into it.
مثال کار شده · lcm(4, 6)
قدم به قدم
- \gcd(4, 6)
Use Euclid's algorithm: replace the larger number by its remainder on division by the smaller, until the remainder is 0.
- 6 = 1 \times 4 + 2
Divide 6 by 4: quotient 1, remainder 2.
- 4 = 2 \times 2 + 0
Divide 4 by 2: quotient 2, remainder 0.
- \gcd(4, 6) = 2
Euclid gives the gcd.
- \operatorname{lcm}(4, 6) = \frac{4 \times 6}{\gcd(4, 6)} = \frac{24}{2} = 12
lcm × gcd = a × b, so divide the product by the gcd.
جواب رو نشون بده
حالا تو يه مساله انتخاب کن، يا خودت رو بنويس يا بکشي هر گام، يه تصوير، جواب مخفي ميشه تا وقتي که تو بپرسي
نمادهای استفاده‌شده در اینجا
هر نماد را برای تعریف کامل، تصویر و معنی هر حرف در آن بزنید.
چطور: Universal properties, limits and adjunctions
- Use Euclid's algorithm: replace the larger number by its remainder on division by the smaller, until the remainder is 0.
- Divide 6 by 4: quotient 1, remainder 2.
- Divide 4 by 2: quotient 2, remainder 0.
- Euclid gives the gcd.
- lcm × gcd = a × b, so divide the product by the gcd.
سوالاتي که مردم ميپرسن
What is a functor?
A map between categories that sends objects to objects and arrows to arrows while respecting composition. Taking the fundamental group of a space is a functor from spaces to groups.