„A maga képére...” – Misszionáriusok fotográfiái mint az egyháztörténet forrásai : „In his own image” – Photographs of Missionaries as the Source of Church History

„The picture speaks for itself” – says the proverb, but how do we hear what it says and how do we understand its words? We are now in the age of visual information where visual content plays a role in every part of life. But we do not spend enough time looking at the pictures in detail. We spend a flash of time with them, and the pictures do not affect our consciousness, but our emotions. From this follows the question of how can we, as social scientists extract the contents of the photos? How can a photo be the source of the church history? This essay cannot, of course, give a perfect answer to the question, but it gives a brief introduction to the so-called „skills of visual literacy”, based on some photography relevant to Church history

Norm convergence of Fejér means of certain functions with respect to UDMD product systems.

In this paper we investigate the norm convergence of Feje'r means of functions belonging to Lipschitz classes in that case when the orthonormal system is the unitary dyadic martingale différence system (UDMD system). We give an estimation of the order of norm convergence. The resuit of the paper shows a sharp constrast between the corresponding known Statement which relatives to the ordinary Walsh-Paley system