Torsion-free abelian groups of finite rank projective as modules over their endomorphism rings Since Richman and Walker [4] characterized modules over PID's which are injective as modules over their endomorphism rings, various homological properties of abelian groups as modules over their endomorphism ...
A module A is torsion if tA = A; a module A is torsion-free if tA = 0. We have remarked, in Chapter 4, that the module A/tA is always torsion-free; thus every module (over a domain) is an extension of a torsion module by a torsion-free module. Exercise 7.13 shows that such...
Even though spring theory and accumulated practical knowledge have developed over the years, the range of materials, sizes and shapes is so great that the design process represents a severe engineering challenge. Even with the assistance of a computer, designers often need to oversimplify the spring...