# Implement intersecting product using Möbius transform #14954

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merged 2 commits into from Jul 23, 2018

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### sidhantnagpal commented Jul 22, 2018

#### Brief description of what is fixed or changed

Möbius transform is used for calculating intersecting product (returns list of sum of products of elements grouped by bitwise AND of the corresponding sequence indices).
Usage for the same is:

``````>>> from sympy import symbols, S, I, intersecting_product
>>> u, v, x, y, z = symbols('u v x y z')

>>> intersecting_product([u, v], [x, y])
[u*x + u*y + v*x, v*y]

>>> intersecting_product([u, v, x], [y, z])
[u*y + u*z + v*y + x*y + x*z, v*z, 0, 0]
``````

``` Add intersecting product ```
``` f94b061 ```

### jksuom reviewed Jul 22, 2018

 The indices of each argument, considered as bit strings, correspond to subsets of a finite set. The intersecting product of given sequences is a sequence which contains

#### jksuom Jul 22, 2018

Member

Maybe `the sequence`?

### jksuom reviewed Jul 22, 2018

 subsets of a finite set. The intersecting product of given sequences is a sequence which contains sum of products of the elements of the given sequences grouped by

#### jksuom Jul 22, 2018

Member

Should this be plural? `the sums`?

#### sidhantnagpal Jul 22, 2018

Author Member

Yes, seems clearer.

``` Improve docs of covering and intersecting product ```
``` 066b371 ```

### jksuom merged commit `f0bfc2c` into sympy:master Jul 23, 2018 1 check passed

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