Later a bouquet of Krasnosel 'skii-type theorems was discovered; see [1,2, 3, 4,16,17]. Apart from the usual line segment visibility and starshapedness several other notions of starshaped set and visibility have been investigated in the past years: d-starshaped sets in metric and normed spaces [14,15,16,17], starshaped sets in graphs [14,171, staircase visibility [5,10,12], rectangular visibili...
