0

While studying differential geometry of Manifolds,one has surely come across the space of all alternating $k$-tensors on a vector space $V$ (say of finite dimension $n$). We denote it by $$ \Lambda^k(V) := \{T\in {V^{\otimes^k}}: T\text{ is an alternating tensor} \} $$ which has a canonical basis $\{e_{i_1}\wedge e_{i_2}\wedge\cdots\wedge e_{i_k}: 1\leq i_1<i_2<\cdots<i_k\leq n\}$. Now suppose $U$ is an open set in $\mathbb R^n$. Now, a differential $k$ form on $U$ is defined to be a map $$ \omega: U \to \bigcup_{p\in U} \Lambda^k(T_pU) $$ such that the following are satisfied:

$(1)\quad \omega(p)\in \Lambda^k(T_pU)$,

$(2)\quad$ The functions $c_{i_1,\ldots,i_k}: U\to \mathbb R$ are $C^\infty$ smooth for all $1\leq i_1<\cdots<i_k\leq n$, where $$ \omega(p) = \sum_{1\leq i_1<\cdots<i_k\leq n} c_{i_1,i_2,\ldots,i_k}(p) \, dx_{i_1}|_p \wedge \cdots \wedge dx_{i_k}|_p $$ is the unique basis representation of $\omega(p)$ in terms of the canonical basis.

I want to know if there is a specific standard name for the disjoint union $\bigcup_{p\in U}\Lambda^k(T_pU)$ similar to what we have in case of vector fields where we call $TM=\bigcup_{p\in M} T_p(M)$, which is the disjoint union of the tangent spaces, by the name Tangent Bundle and we can think of a vector field as a section of the tangent bundle.

I am curious to know whether we have anything similar for the alternating tensors and whether we can look at the differential forms as a section of the bundle.

Note

I am not familiar with bundles and know very little about them. So, I need some help to get my question answered. Is there anyone who can provide me with a satisfactory one and at the same time give me some insight about what the bundle means for alternating tensors?

Sammy Black
  • 25,273
  • “$k^{th}$ exterior power of $TM$”, (or maybe you want to specialize to $U$ for whatever reason) thats what its called. In general for “any” vector space operation (direct sum, tensor product, exterior power, Hom spaces) there is a corresponding notion at the vector bundle level. For the terminology and notation see Clarification on notation regarding fields, forms, and exterior algebra. For showing that the results are actually vector bundles, you really just need to unwind definitions or just refer to a standard textbook. – peek-a-boo Nov 04 '23 at 06:30

0 Answers0