Proving h is a Differential Form

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SUMMARY

The discussion centers on proving that the expression h = e_1 ∧ e_2 + e_3 ∧ e_4 qualifies as a differential form, where e_1, e_2, e_3, and e_4 represent basis elements. The key argument presented is that these basis elements can be interpreted as differentials (e.g., e_1 = dx, e_2 = dy, e_3 = dz, e_4 = dt), leading to the expression dx ∧ dy + dz ∧ dt. The anti-symmetry property of the wedge product is emphasized, particularly that dx ∧ dx = 0. Additionally, the need to demonstrate the smoothness of the differential form is highlighted.

PREREQUISITES
  • Understanding of differential forms and their properties
  • Familiarity with the wedge product and its anti-symmetry
  • Knowledge of smooth functions and sections in differential geometry
  • Basic concepts of calculus in multiple dimensions
NEXT STEPS
  • Study the properties of differential forms in detail
  • Learn about the wedge product and its applications in differential geometry
  • Explore the concept of smooth sections and projection maps
  • Investigate examples of differential forms in various coordinate systems
USEFUL FOR

This discussion is beneficial for students and researchers in mathematics, particularly those focusing on differential geometry, as well as anyone interested in the theoretical foundations of differential forms.

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Hello,

I try to understand differential forms. For istance i want to prove that
h=e_1\wedge e_2 + e_3\wedge e_4
is a differential form, where e_1,..,e_4 are elements of my basis.



Do you have a idea, why this is a differential form?

Regards
 
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First, your 'basis' elements are themselves "differentials". If you think of e_1= dx, e_2= dy, e_3= dz, and e_4= dt then e_1\wedge e_2+ e_3\wedge e_4= dxdy+ dzdt. It would convert the function f(x,y,z, t) into
\int\int f(x,y,z,t) dxdy+ f(x,y,z,t)dzdt

The "wedge", \wedge, is there because this product is "anti-symmetric" dx\wedge dy= -dy\wedge dx so the, in particular, such things as "dx\wedge dx" will be 0.
 
Hello,

thank you, but why it is a differential form? We have defined differential form as a smooth section of the projection map.
Therefore i have to show this. But for instance i do not see why it is smooth.

Regards
 

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