# Extension and contraction of I to D^-1R

#### Peter

##### Well-known member
MHB Site Helper
At the bottom of page 708 in Dummit and Foote (Chapter 15, Section 15.4 Localization) we find the definition of the extension and contraction of ideals.

The notation is similar to $$\displaystyle I^e$$ and $$\displaystyle I^c$$ except that the superscripts e and c occur before the I.

Peter

#### MarkFL

Staff member
Use the codes:

^eI to get: $$\displaystyle ^eI$$

^cI to get: $$\displaystyle ^cI$$

#### Peter

##### Well-known member
MHB Site Helper
Use the codes:

^eI to get: $$\displaystyle ^eI$$

^cI to get: $$\displaystyle ^cI$$

Thanks Mark

Appreciate the help.

Peter

MHB Math Scholar