mcastillo356's latest activity
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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.
You need to understand the words. As I see it, Simmons uses the following terms: ##f\, : \,X\longrightarrow Y## mapping ##X## is the... -
mcastillo356 replied to the thread B Onto set mapping is the surjective set mapping, and into injective?.I'm working on the Schroether-Bernstein theorem, this is, the next step in the textbook "Introduction to topology and modern analysis"...
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mcastillo356 reacted to PeroK's post in the thread B Onto set mapping is the surjective set mapping, and into injective? with
Haha.
Whether you use into and/or onto is upto you! -
mcastillo356 reacted to Gavran's post in the thread B Onto set mapping is the surjective set mapping, and into injective? with
Informative.
To be on the set means occupying the whole set in a particular way and the word “onto” follows the definition of a surjective function... -
Kind of like the Seal Team 6 rehearsals for the Osama Bin Laden raid... :wink:
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mcastillo356 replied to the thread B Onto set mapping is the surjective set mapping, and into injective?.Yes. Simmons is being precise. Into means inyective. That's accurate, indeed. Thanks, @fresh_42 !
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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.
Say, we have ##f\, : \,A\longrightarrow B.## ##f## is onto if it is surjective, i.e., ##\forall\,b\in B\,\exists\,a\in A\, ...
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mcastillo356 posted the thread B Onto set mapping is the surjective set mapping, and into injective? in Set Theory, Logic, Probability, Statistics.The textbook is being fine. I asked the forum for some introduction to topology, and decided to start with Simmon`s. This naive question...
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mcastillo356 reacted to PeterDonis's post in the thread Does it make sense to build new radio telescopes? with Like.
So you think advancing science is stupid? Neither does understanding "the structure of the Universe", or indeed much scientific...
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mcastillo356 reacted to fresh_42's post in the thread Does it make sense to build new radio telescopes? with Like.
The German Wikipedia page lists five big scientific goals. I wouldn't call that negligible. We are a species that is curious and strives...
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mcastillo356 reacted to russ_watters's post in the thread How do people explore new ideas in physics? with Like.
There's really no way around the fact that the barrier to entry (being educated in physics) is required for practical reasons. There's...
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mcastillo356 reacted to phinds's post in the thread Study: Social media probably can’t be fixed with Like.
Australia has banned all social media for those under 16: Yes, Australia has indeed banned social media access for individuals under...
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mcastillo356 reacted to elias001's post in the thread Topology Introductory Topology online textbook recommendations with Informative.
@mcastillo356 Try either: Introduction to Metric and Topological Spaces by Wilson Alexander Sutherland Metric Spaces by Mícheál...
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mcastillo356 replied to the thread B Is this the right set mapping notation for a limit in two variables?.In fact, the cartesian coordinates are continous, and sine function too; this means the value of the limit at any points ##(x,\,y)##...