On a minimax theorem: an improvement, a new proof and an overview of its applications
@article{Ricceri2016OnAM, title={On a minimax theorem: an improvement, a new proof and an overview of its applications}, author={Biagio Ricceri}, journal={arXiv: Functional Analysis}, year={2016} }
Theorem 1 of [14], a minimax result for functions $f:X\times Y\to {\bf R}$, where $Y$ is a real interval, was partially extended to the case where $Y$ is a convex set in a Hausdorff topological vector space ([15], Theorem 3.2). In doing that, a key tool was a partial extension of the same result to the case where $Y$ is a convex set in ${\bf R}^n$ ([7], Theorem 4.2). In the present paper, we first obtain a full extension of the result in [14] by means of a new proof fully based on the use of…
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References
SHOWING 1-10 OF 28 REFERENCES
A strict minimax inequality criterion and some of its consequences
- Mathematics
- 2012
In this paper, we point out a very flexible scheme within which a strict minimax inequality occurs. We then show the fruitfulness of this approach presenting a series of various consequences. Here is…
Well-posedness of constrained minimization problems via saddle-points
- MathematicsJ. Glob. Optim.
- 2008
A very general well-posedness result is proved for a class of constrained minimization problems of which the following is a particular case: Let X be a Hausdorff topological space and J, Phi: X be two non-constant functions such that J has sequentially compact sub-level sets and admits a unique global minimum in X.
Nonlinear fredholm maps of index zero and their singularities
- Mathematics
- 1978
Let F: X -* Y be a C I Fredholm map of index zero between two Banach spaces. Defining the singular set B = (xlF'(x) is not suijective}, we study the local and global effect of B on the map F. In…
Integral functionals on $L^p$-spaces: infima over sub-level sets
- Mathematics
- 2013
In this paper, we establish the following result: Let $(T,{\cal F},\mu)$ be a $\sigma$-finite measure space, let $Y$ be a reflexive real Banach space, and let $\varphi, \psi:Y\to {\bf R}$ be two…
On infinite-dimensional features of proper and closed mappings
- Mathematics
- 1986
We consider some global properties of continuous proper and closed maps acting in infinite-dimensional Frechet manifolds. These essentially infinite-dimensional features are related to the following…
Singular points of non-monotone potential operators
- Mathematics
- 2014
In this paper, we establish some results about the singular points of certain non-monotone potential operators. Here is a sample: If $X$ is an infinite-dimensional reflexive real Banach space and if…
Fixed points of nonexpansive potential operators in Hilbert spaces
- Mathematics
- 2012
In this paper, we show the impact of certain general results by the author on the topic described in the title. Here is a sample:Let (X,〈⋅,⋅〉) be a real Hilbert space and let T:X→X be a nonexpansive…
The problem of minimizing locally a ² functional around non-critical points is well-posed
- Mathematics
- 2007
In this paper, we prove the following general result: Let X be a real Hilbert space and J : X → R a C 1 functional, with locally Lipschitzian derivative. Then, for each x 0 ∈ X with J'(x 0 ) ≠ 0,…