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5.1.52 imap
Syntax:
imap ( ring_name, name )
Type:
- number, poly, vector, ideal, module, matrix or list
(the same type as the second argument)
Purpose:
- identity map on common subrings.
imap is the map between rings
and qrings with compatible ground fields which is the identity on
variables and parameters of the same name and 0 otherwise.
(See map for a description of possible mappings between
different ground fields).
Useful for mapping from a homogenized ring to the original ring or
for mappings from/to rings with/without parameters. Compared with
fetch , imap uses the names of variables and parameters.
Unlike map and fetch imap can map parameters to variables.
Example:
See
fetch;
homog;
map;
qring;
ring.
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