# Talk:Network motif

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## Definition is incomplete

First sentence of definition:

Let and be two graphs, graph G′ is a sub-graph of graph G (written as G′ ⊆ G) if V′ ⊆ V and E′ ⊆ E ∩ (V′ × V′).

What is V? What is E? What is the cross operator for graphs? What is the intersect operator? What does this sentence mean?

--Ar-Pharazôn (talk) 19:19, 15 April 2013 (UTC)

The cross operator is the set theoretic Cartesian product, which, apparently, should be evident from the use of the subset symbol, ⊆. For more information I refer you to the "basic concepts and notation" section of the Wikipedia article on set theory.

Boris Breuer (talk) 11:58, 26 October 2013 (UTC)

## Error

The first sentence of the Definition starts as "Let {{{1}}} and {{{1}}} be two graphs". The {{{1}}} should have a special meaning in the Wiki source? There are many {{{1}}}-s in the description of the picture as well. -- Harp (talk) 17:19, 4 July 2013 (UTC)

## First paragraph

I believe there is a problem in the very first paragraph: "All networks, including biological networks, social networks, technological networks (e.g., computer networks and electrical circuits) and more, can be represented as graphs, which include a wide variety of subgraphs. One important local property of networks are so-called network motifs, which are defined as recurrent and statistically significant sub-graphs or patterns."

As far as I know, network motifs is a term just applied in gene expression, in the best case, biological networks. See that there is no reference for that claim, for mine I have several (e.g. Sara Green. Revisiting Generality in Biology: Systems Biology and the Quest for Design Principles ). I propose to add the term biological network instead of networks:

New Sentence:

"All networks, including biological networks, social networks, technological networks (e.g., computer networks and electrical circuits) and more, can be represented as graphs, which include a wide variety of subgraphs. One important local property of biological networks are so-called network motifs, which are defined as recurrent and statistically significant sub-graphs or patterns." and cite Green and Alon, the latter is already present in the reference list.

Jorge Pires (talk) 14:45, 23 August 2015 (UTC)