
An infinitary version of the notion of free products has been introduced and investigated by G.Higman. Let G_i (for i in I) be groups and ast_{i in X} G_i the free product of G_i (i in X) for X Subset I and p_{XY}: ast_{i in Y} G_{i}->ast_{i in X} G_{i} the canonical homomorphism for X subseteq Y Subset I. (X Subset I denotes that X is a finite subset of I.) Then, the unrestricted free product is the inverse limit lim (ast_{i in X} G_i, p_{XY}: X subseteq Y Subset I). We remark ast_{i in emptyset} G_i= {e} . We prove: Theorem: Let F be a free group. Then, for each homomorphism h:lim ast G_i-> F there exist countably complete ultrafilters u_0,...,u_m on I such that h = h . p_{U_0 cup ... cup U_m} for every U_0 in u_0, ...,U_m in u_m. If the cardinality of the index set I is less than the least measurable cardinal, then there exists a finite subset X_0 of I and a homomorphism overline {h}: ast_{i in X_0}G_i-> F such that h= overline {h} . p_{X_0}, where p_{X_0}: lim ast G_i->ast_{i in X_0}G_i is the canonical projection.
Free products of groups, free products with amalgamation, Higman-Neumann-Neumann extensions, and generalizations, Algebra and Number Theory, Measurable cardinal, Free σ-product, Inverse limit, Mathematics - Logic, Mathematics - Rings and Algebras, Group Theory (math.GR), Non-commutative, Free complete product, General structure theorems for groups, Specker phenomenon, Rings and Algebras (math.RA), FOS: Mathematics, unrestricted free products, Logic (math.LO), Mathematics - Group Theory
Free products of groups, free products with amalgamation, Higman-Neumann-Neumann extensions, and generalizations, Algebra and Number Theory, Measurable cardinal, Free σ-product, Inverse limit, Mathematics - Logic, Mathematics - Rings and Algebras, Group Theory (math.GR), Non-commutative, Free complete product, General structure theorems for groups, Specker phenomenon, Rings and Algebras (math.RA), FOS: Mathematics, unrestricted free products, Logic (math.LO), Mathematics - Group Theory
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 2 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
