The principle of equivalence and projective structure in space-times
The principle of least action for test particles in a four-dimensional spacetime embedded in 5D
The Principle of Non-Gravitating Vacuum Energy and some of its consequences
The Principle of Relativity and Inertial Dragging
The Principle of Symmetric Criticality in General Relativity
The Principle of the Fermionic Projector: An Approach for Quantum Gravity?
The Principles of Self Creation Cosmology and its Comparison with General Relativity
The Probability for Primordial Black Holes
The probability of inflation in Loop Quantum Cosmology
The Problem of Classical Limit in Quantum Cosmology: The effective action language
The problem of singularities and chaos in cosmology
The problem of singularities of higher order curvature corrections in four dimensional string gravity
The problem of time and gauge invariance in the quantization of cosmological models. I. Canonical quantization methods
The problem of time and gauge invariance in the quantization of cosmological models. II. Recent developments in the path integral approach
The Problem of Time and Quantum Black Holes
The Problem of Time and Quantum Cosmology in the Relational Particle Mechanics Arena
The problem of time in parametrized theories
The Problem of Time in Quantum Gravity
The Problems of Time and Observables: Some Recent Mathematical Results
The Proca-field in Loop Quantum Gravity