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# Maths Help, (Sets, Functions and Relations)

Not sure if this is the right spot but I guess it is related to programming. I really need some help, maybe I am stupid or something but all this maths really confuses me.

I have been trying to answer this question for hours and everything just confuses me. My best guess is that it is injective(one to one) as each element of the co domain is mapped to one element and the last element b9 is not mapped.

As for the second question I have no clue.

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Spoiler

not the foggiest idea, sorry my dude.

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for the first question: Did you checked definitions?

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1 minute ago, James Evens said:

for the first question: Did you checked definitions?

Yes, yet is still confusing there are 8 inputs and 9 possible outputs. The 8 inputs go to the 8 outputs that is clear however what about the parity bit does it get mapped or is just left alone. If it is left alone then it is injective if it is mapped then it is subjective but it can also be both

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32 minutes ago, Tonny said:

Yes, yet is still confusing there are 8 inputs and 9 possible outputs. The 8 inputs go to the 8 outputs that is clear however what about the parity bit does it get mapped or is just left alone. If it is left alone then it is injective if it is mapped then it is subjective but it can also be both

You have two Sets (B8 [8 digits] and B9 [9 digits]) and B9 is described by f:B8 (f:B8 -> B9)

So far clear?

For injectiv you are asking are there any two or more elements of B8 represented by the same element of B9. If you find a set of B8s which have the same B9 then it is not injectiv.

For surjectiv it is the same. Now you ask is every value of B9 represented by a element of B8. For this example:

- injectiv

- not surjectiv

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20 minutes ago, James Evens said:

You have two Sets (B8 [8 digits] and B9 [9 digits]) and B9 is described by f:B8 (f:B8 -> B9)

So far clear?

For injectiv you are asking are there any two or more elements of B8 represented by the same element of B9. If you find a set of B8s which have the same B9 then it is not injectiv.

For surjectiv it is the same. Now you ask is every value of B9 represented by a element of B8. For this example:

- injectiv

- not surjectiv

I think I get it now.

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discrete math.... I hate these stuff.

it is not related to programming although it does concern computer scientists cuz... well, these people are really mathematicians at heart and specializes in algorithms. I remember going to my calculus TA for help with my computer science topics like these. lol

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6 hours ago, wasab said:

discrete math.... I hate these stuff.

it is not related to programming although it does concern computer scientists cuz... well, these people are really mathematicians at heart and specializes in algorithms. I remember going to my calculus TA for help with my computer science topics like these. lol

In my cs degree the most "algorithms" I got was a bubble sort I'm assembly.

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