@10:47 "D ⊆ inverseR(J)," states ___the set of all students___ (denoted by D) happens to be a subset of ___the set of subjects that have registered students___ (denoted by inverseR(J)). It's *NOT* true because the set of all students (that is, D) includes/contains the element Adam but the set of subjects that have registered students (that is, inverseR(J)) does not include/contain some subject that has registered the student Adam -- D ⊆ inverseR(J) is {Jason, Joan, Yihui, Adam} ⊆ {Jason, Joan, Adam} and is False.
At 10:45, why not use D = R^(-1) (J) to indicate that every student is registered for some subject? It is against my intuition to use the "is a subset of" symbol because it is impossible for the domain of discourse to have fewer elements than the set of students who are registered for some subject.
Something is troubling me... At 6:53 the teacher uses the pipe symbol " | " and the dot symbol " . " but both are translated as " such as " Is there a difference between those two symbols ?
Poor teaching way. He's actually reading the slides. If you can understand the materials in the reading notes, then you will not understand what he read.
Great video, at 22:39, you will see the most common term "function" we used in computer science. A formal and concise definition
so great for gaining a more intuitive understanding of what relations simply and fundamentally are!
@10:47 "D ⊆ inverseR(J)," states ___the set of all students___ (denoted by D) happens to be a subset of ___the set of subjects that have registered students___ (denoted by inverseR(J)). It's *NOT* true because the set of all students (that is, D) includes/contains the element Adam but the set of subjects that have registered students (that is, inverseR(J)) does not include/contain some subject that has registered the student Adam -- D ⊆ inverseR(J) is {Jason, Joan, Yihui, Adam} ⊆ {Jason, Joan, Adam} and is False.
14:34 there is a missing arrow from TLP to Yihui
At 10:45, why not use
D = R^(-1) (J)
to indicate that every student is registered for some subject?
It is against my intuition to use the "is a subset of" symbol because it is impossible for the domain of discourse to have fewer elements than the set of students who are registered for some subject.
Because one of the D, Adam, is technically not a stuDent being that (he/she/they) is not registered for ANY of the 4 listed subJects.
2:26 Adam looks more like me of school times. 😂
Something is troubling me...
At 6:53 the teacher uses the pipe symbol " | " and the dot symbol " . " but both are translated as " such as "
Is there a difference between those two symbols ?
+1 same doubt
13 july
Adam doesn't feel good
Why is the label for that group called stuDent when no course registers him?
Comparing the way that Khan Academy uses and the power point way, the only thing that students can feel is confusing.
There's definitely better teaching software out there than PowerPoint, but maybe we shouldn't be too picky considering it's offered to us for free
confusion*
Poor teaching way. He's actually reading the slides. If you can understand the materials in the reading notes, then you will not understand what he read.
I am sowy
you are missing the context. This is part of a course and htere was a reading assignment to be completed before this