# Formation and Dissolution Constraints for Exponential Family Random Graph Models

### Description

This page describes the network sample space constraints
that are included with the
`tergm`

package. For more information, and
instructions for using constraints, see
`ergm-constraints`

and `ergm`

.

### Constraints implemented in the `tergm`

package

`atleast(nw)`

*The Formation Constraint:*Preserve all ties in network`nw`

. Only dyads that are not ties in`nw`

may be changed.`atmost(nw)`

*The Dissolution Constraint:*Prevent all nonties in network`nw`

. Only dyads that have ties in`nw`

may be changed.

### References

Krivitsky PN, Handcock MS (2010). A Separable Model for Dynamic Networks. http://arxiv.org/abs/1011.1937

Goodreau SM, Handcock MS, Hunter DR, Butts CT, Morris M (2008a).
A statnet Tutorial.
*Journal of Statistical Software*, 24(8).
http://www.jstatsoft.org/v24/i08/.

Hunter, D. R. and Handcock, M. S. (2006)
*Inference in curved exponential family models for networks*,
Journal of Computational and Graphical Statistics.

Hunter DR, Handcock MS, Butts CT, Goodreau SM, Morris M (2008b).
ergm: A Package to Fit, Simulate and Diagnose
Exponential-Family Models for Networks.
*Journal of Statistical Software*, 24(3).
http://www.jstatsoft.org/v24/i03/.

Krivitsky PN (2012). Exponential-Family Random Graph Models for Valued
Networks. *Electronic Journal of Statistics*, 2012, 6,
1100-1128. `doi:10.1214/12-EJS696`

Morris M, Handcock MS, Hunter DR (2008).
Specification of Exponential-Family Random Graph Models:
Terms and Computational Aspects.
*Journal of Statistical Software*, 24(4).
http://www.jstatsoft.org/v24/i04/.