# PushForward -- methods to compute the pushforward of a module along a ring map

## Description

Given a ring map $f \colon A \to B$, and a $B$-module $M$, $M$ has the structure of an $A$-module, and if this module is finitely generated over $A$, the routine pushFwd in this package will compute such an $A$-module. This is also functorial, in that if a map of $B$-modules (both of which are finitely generated over $A$), then pushFwd(RingMap,Matrix) will return the induced map on $A$-modules.

In an algebraic sense, this is really a pull back, but thinking geometrically, the functions here implement the push forward of a module (or sheaf).

This package was originally implemented by Claudiu Raicu, some changes were introduced by Karl Schwede, and later by David Eisenbud and Mike Stillman.

## Version

This documentation describes version 0.6 of PushForward.

## Source code

The source code from which this documentation is derived is in the file PushForward.m2.

## For the programmer

The object PushForward is .