To clarify all your doubts about the concave lens and convex lens, students can read this article. Here, the difference between a concave lens and a convex lens has been discussed in detail.

Concave vs Convex Mirror: Know hеrе what is thе diffеrеncе bеtwееn Concave vs Convex Mirror. Concavе mirrors curvе inward and crеatе both rеal and virtual imagеs. Convеx mirrors ...

In a previous paper, we showed that gradient maps of exponentially concave functions provide solutions to a Monge–Kantorovich optimal transport problem and give a better gradient approximation than ...

KRISTIAN BREDIES, HONGPENG SUN, PRECONDITIONED DOUGLAS–RACHFORD SPLITTING METHODS FOR CONVEX-CONCAVE SADDLE-POINT PROBLEMS, SIAM Journal on Numerical Analysis, Vol. 53, No. 1 (2015), pp. 421-444 ...