Yes, if a Nobel prize is given for two different topics (for three people, first person - one topic, other two - another topic) then 1/2, 1/4, 1/4 shares will be assigned, for example the prize in physics in 2019 [1].
Yes, it can also be split 1/2 + 1/4 + 1/4, e.g. when two competing efforts are recognized, one of which was two people. The rule that at most three people can share the pize can make this awkward.
(x 3)
Can someone elaborate on these weights ? Are there occurrences where the attribution weights are different between laureates ?