On arbitrages arising from honest times

In the context of a general continuous financial market model, we study whether the additional information associated with an honest time gives rise to arbitrage profits. By relying on the theory of progressive enlargement of filtrations, we explicitly show that no kind of arbitrage profit can ever be realised strictly before an honest time, while classical arbitrage opportunities can be realised exactly at an honest time as well as after an honest time. Moreover, stronger arbitrages of the first kind can only be obtained by trading as soon as an honest time occurs. We carefully study the behavior of local martingale deflators and consider no-arbitrage-type conditions weaker than NFLVR.Comment: 25 pages, revised versio

Convergence in measure under Finite Additivity

We investigate the possibility of replacing the topology of convergence in probability with convergence in $L^1$. A characterization of continuous linear functionals on the space of measurable functions is also obtained

Heart echinococcus cyst as an incidental finding: early detection might be life-saving

We present a 46-year-old female smoker who was admitted to the emergency department of our hospital due to cough with blood-tinged sputum for the last four days before admission. Using echocardiography and Multi-Detector Computed Tomography (MDCT) heart Echinococcosis was diagnosed. Echinococcosis is a severe health issue in some geographical regions of the world. Hydatid infection of the heart is rare and the clinical presentation is usually insidious but there is always the lethal hazard of cyst perforation. Early diagnosis and an integrated treatment strategy are crucial. The results of surgical treatment of heart echinococcosis are better than the conservative strategy only. Extraction of the cyst combined with chemotherapy peri or post operative aiming to decrease the recurrences, consists the lege artis method of encountering this medical entity. Surgical excision was performed and the patient had an uneventful recovery and follow up at six and twelve months

A simple characterization of tightness for convex solid sets of positive random variables

We show that for a convex solid set of positive random variables to be tight, or equivalently bounded in probability, it is necessary and sufficient to be radially bounded, i.e. that every ray passing through one of its elements eventually leaves the set. The result is motivated by problems arising in mathematical finance

A time before which insiders would not undertake risk

A continuous-path semimartingale market model with wealth processes discounted by a riskless asset is considered. The numéraire portfolio is the unique strictly positive wealth process that, when used as a benchmark to denominate all other wealth, makes all wealth processes local martingales. It is assumed that the numéraire portfolio exists and that its wealth increases to infinity as time goes to infinity. Under this setting, an initial enlargement of the filtration is performed, by including the overall minimum of the numéraire portfolio. It is established that all nonnegative wealth processes, when stopped at the time of the overall minimum of the numéraire portfolio, become local martingales in the enlarged filtration. This implies that risk-averse insider traders would refrain from investing in the risky assets before that time. A partial converse to the previous result is also established in the case of complete markets, showing that the time of the overall minimum of the numéraire portfolio is in a certain sense unique in rendering undesirable the act of undertaking risky positions before it. The aforementioned results shed light t