# Start a new discussion

## Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

## Discussion Tag Cloud

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

• CommentRowNumber1.
• CommentAuthorzskoda
• CommentTimeNov 4th 2011

I have created some genuine content at implicit function theorem. I’d like to hear the comments on the global variant, which is there, taken from Miščenko’s book on vector bundles in Russian (the other similar book of his in English, cited at vector bundle, is in fact quite different).

• CommentRowNumber2.
• CommentAuthorTodd_Trimble
• CommentTimeNov 4th 2011
• (edited Nov 4th 2011)

I disagree with the definition given of regular value. The definition with which I am familiar is that $q$ is regular if for each $p \in f^{-1}(q)$, the map $T_p(f): T_p(M) \to T_q(N)$ has maximal rank (i.e., $\min(\dim(M), \dim(N))$). Perhaps this is not important for your application, but it is important otherwise.

• CommentRowNumber3.
• CommentAuthorzskoda
• CommentTimeNov 4th 2011
• (edited Nov 4th 2011)

Hm, I quoted here Miščenko, but my 1988 notebook gives the same definition (regular value means that the tangent map from any point in the preimage is surjective). The same is in 5.6 in Bröcker-Jänich, in the standard textbook Hirsch, chapter 1, just before theorem 3.2 and in Bott-Tu just before theorem 4.9. Your definition is weaker, I heard of it as well, but the sample of the standard textbooks agrees with what I said. P.S. also the same in S. Sternberg, Lectures on differential geometry, Ch. II, Def. 3.3.

• CommentRowNumber4.
• CommentAuthorzskoda
• CommentTimeNov 4th 2011

By the way, is word (?) “dimensionalysis” a typo at exponential map or it is intended ?

• CommentRowNumber5.
• CommentAuthorTodd_Trimble
• CommentTimeNov 4th 2011

Unfortunately, I can’t effectively investigate this further until I get power back at my house. (I’m working from an iPad for my Internet connection, and living like a refugee at other people’s houses.)

• CommentRowNumber6.
• CommentAuthorTobyBartels
• CommentTimeNov 4th 2011

My recollection agrees with Zoran’s definition. When $\dim(M) \lt \dim(N)$, I can see the importance of asking whether $T_p(f)$ has rank $dim(M)$, but it seems to me to be a different question. But both are generalisations of the case from ordinary calculus, so I could imagine the same terminology being used.

• CommentRowNumber7.
• CommentAuthorTobyBartels
• CommentTimeNov 4th 2011

We discussed “dimensionalysis” before.

• CommentRowNumber8.
• CommentAuthorTodd_Trimble
• CommentTimeNov 4th 2011

It’s annoying to me that I may be misremembering, but I’m just about prepared to admit that I am indeed. I’ll come back if I have anything useful to add.

• CommentRowNumber9.
• CommentAuthorTobyBartels
• CommentTimeNov 4th 2011

It looks like I just massively rewrote the article, but really I just added some links!

• Please log in or leave your comment as a "guest post". If commenting as a "guest", please include your name in the message as a courtesy. Note: only certain categories allow guest posts.
• To produce a hyperlink to an nLab entry, simply put double square brackets around its name, e.g. [[category]]. To use (La)TeX mathematics in your post, make sure Markdown+Itex is selected below and put your mathematics between dollar signs as usual. Only a subset of the usual TeX math commands are accepted: see here for a list.

• (Help)