nLab Phil Ehlers

Phil Ehlers was a postgraduate student (1989-1993) at Bangor, working in the team of Ronnie Brown and Tim Porter, who was Phil’s doctoral supervisor.

Selected writings

On simplicial groupoids (thanks are due to Stephen Gaito for preparing a scanned version with Phil’s permission):

• Philip J. Ehlers, Simplicial groupoids as models for homotopy type, Master’s thesis (1991) [pdf]

also known as sSet-enriched groupoids:

• Philip J. Ehlers, Algebraic Homotopy in Simplicially Enriched Groupoids, PhD thesis, University of Wales Bangor (1993) [pdf]

He has published several papers based on his work (jointly with Tim Porter). These include:

• P. J. Ehlers and Tim Porter, Joins for (Augmented) Simplicial Sets, Jour. Pure Applied Algebra, 145 (2000) 37-44

  (arXiv) .

• P. J. Ehlers and Tim Porter, Varieties of simplicial groupoids, I, Crossed complexes, Jour. Pure Applied Algebra, 120 (1997) 221 - 233; Erratum: Jour. Pure Applied Algebra, 134 (1999) 221-233.

• P. J. Ehlers and Tim Porter, Ordinal subdivision and special pasting in quasicategories, Advances in Math. 217 (2007), No 2. pp 489-518.

category: people