2139., [2] International Centre for Diffraction Data, Newtown Square, PA 19073-3273 U.S.A., [3] Von Dreele R.B. (2000) 49 Denver X-ray Conference, Colorado, [4] The Rietveld Method, Ed. R.A. Young (1993) International Union of Crystallography, Oxford University Press) 4 5 6 7 8 2θ, deg In te ns ity ( c /s ) L D Lunar and Planetary Science XXXIV (2003) 1682.pdf

We investigate forcing notions with the rectangle refining property, which is stronger than the countable chain condition, and fragments of Martin’s Axiom for such forcing notions. We prove that it is consistent that every forcing notion with the rectangle refining property has precaliber א1 but MAא1 for forcing notions with the rectangle refining property fails.

The Rietveld method of structure refinement with powder diffraction patterns was originally devised for the analysis of fixed-wavelength (angle-dispersive) neuron data [1] [2] but now constitutes a major breakthrough for the usefulness of X-ray powder data [3]. This powerful method has greatly extended the amount of structural detail which can be obtained routinely from powder diffraction patte...