mcastillo356's latest activity
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The good news is that lithium cell fires will burn themselves out reasonably quickly at high temperature. The bad news is that nearby... -
mcastillo356 reacted to DaveC426913's post in the thread I Midpoint(s) of the unbounded number line with
Informative.
Although, for all we know, this is a fourth-year university Set Theory course. :wink: -
mcastillo356 reacted to FactChecker's post in the thread I Midpoint(s) of the unbounded number line with Informative.
Yes. Any finite number is as good as any other. That goes too far. It's impossible to say that any number is "exactly halfway between...
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It seems that NASA is (temporarily) shut down. https://www.nasa.gov/shutdown/ :frown:
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mcastillo356 reacted to fresh_42's post in the thread RIP Jane Goodall (91), primatologist and conservationist with
Like.
I think we generally still underestimate our fellow animals on this planet. -
mcastillo356 reacted to Gavran's post in the thread B Onto set mapping is the surjective set mapping, and into injective? with Informative.
The first statement of the theorem was published in 1887 by Georg Cantor. If M and N are two such sets that components M' and N' can be...
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mcastillo356 reacted to fresh_42's post in the thread B Onto set mapping is the surjective set mapping, and into injective? with Informative.
Here is another source, in case this is easier. https://web.williams.edu/Mathematics/lg5/CanBer.pdf
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mcastillo356 reacted to fresh_42's post in the thread B Onto set mapping is the surjective set mapping, and into injective? with Like.
If we have an injective map ##f\, : \,A\rightarrow B## then its restriction on the image ##f'\, : \,A \rightarrow f(A)## is bijective.
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mcastillo356 replied to the thread B Onto set mapping is the surjective set mapping, and into injective?.Lemma 2 is difficult to me Why ##A=A_{0}\sim{B_{1}}\sim{A_{2}}\sim{B_{3}}\sim{A_{4}}\sim{\cdots}##? Attempt ##A=A_{0}##...
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mcastillo356 replied to the thread B Onto set mapping is the surjective set mapping, and into injective?.Working hard on it.
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mcastillo356 replied to the thread RIP Robert Redford (89)."The sting", that's my favorite movie. The soundtrack is amazing.
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That was one of the great Oscar travesties. Ordinary People over The Elephant Man and Raging Bull?! Best director and best picture?!
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mcastillo356 reacted to fresh_42's post in the thread B Onto set mapping is the surjective set mapping, and into injective? with Like.
No. We have ##f\, : \,X\longrightarrow Y## and ##g\, : \,Y\longrightarrow X.## No real numbers anywhere. I had ##F=f\circ g\circ f##...
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mcastillo356 replied to the thread B Onto set mapping is the surjective set mapping, and into injective?.##\mathbb{R}^+##?
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mcastillo356 replied to the thread B Onto set mapping is the surjective set mapping, and into injective?.No idea. I can only attempt at it: ##F## could be the identity function? @martinbn says so. Another doubt: The Axiom of Choice is needed?
